WPF开发学生信息管理系统【WPF+Prism+MAH+WebApi】（四）

最近通过WPF开发项目，为了对WPF知识点进行总结，所以利用业余时间，开发一个学生信息管理系统【Student Information Management System】。前三篇文章进行了框架搭建和模块划分，后台WebApi接口编写，以及课程管理模块开发，本文在前三篇基础之上，继续深入开发学生信息管理系统的班级管理和学生管理模块，通过本篇文章，将继续巩固之前的知识点，本文仅供学习分享使用，如有不足之处，还请指正。

涉及知识点

由于班级管理和学生管理的服务端开发，在第二篇文章中以后介绍，所以本篇专注介绍客户端功能的开发。涉及知识点如下：

1. WPF开发中TextBlock，TextBox，DataGrid，Combox等控件的基础使用以及数据绑定等操作。
2. MAH样式的使用，在本示例中MAH主要用于统一页面风格，提高用户体验。
3. HttpClient使用，主要用于访问服务端提供的接口。

业务逻辑

首先班级管理和学生管理既有关联，又相互独立，不像课程管理模块独立存在，不与其他模块存在依赖。所以两个模块一起放在一篇文章进行讲解。关系如下：

1. 学生属于某一班级之学生，所以学生中包含班级信息。
2. 班级中存在班长，班长又属于学生的一个实体。

班级管理

1. 接口访问类ClassesHttpUtil

班级数据表结构和服务接口，在第二篇文章中已有介绍，如有疑问，可前往参考。接口访问类用于封装访问服务端提供的接口。如下所示：

 1 namespace SIMS.Utils.Http
 2 {
 3     public class ClassesHttpUtil:HttpUtil
 4     {
 5         /// 

 6         /// 通过id查询学生信息
 7         /// 
 8         /// 
 9         /// 
10         public static ClassesEntity GetClasses(int id)
11         {
12             Dictionary<string, object> data = new Dictionary<string, object>();
13             data["id"] = id;
14             var str = Get(UrlConfig.CLASSES_GETCLASSES, data);
15             var classes = StrToObject(str);
16             return classes;
17         }
18 
19         public static PagedRequest GetClassess(string? dept, string? grade, int pageNum, int pageSize)
20         {
21             Dictionary<string, object> data = new Dictionary<string, object>();
22             data["dept"] = dept;
23             data["grade"] = grade;
24             data["pageNum"] = pageNum;
25             data["pageSize"] = pageSize;
26             var str = Get(UrlConfig.CLASSES_GETCLASSESS, data);
27             var classess = StrToObject>(str);
28             return classess;
29         }
30 
31         public static bool AddClasses(ClassesEntity classes) {
32             var ret = Post(UrlConfig.CLASSES_ADDCLASSES, classes);
33             return int.Parse(ret)==0;
34         }
35 
36         public static bool UpdateClasses(ClassesEntity classes) {
37             var ret = Put(UrlConfig.CLASSES_UPDATECLASSES, classes);
38             return int.Parse(ret) == 0;
39         }
40 
41         public static bool DeleteClasses(int Id)
42         {
43             Dictionary<string,  string> data = new Dictionary<string, string>();
44             data["Id"] = Id.ToString();
45             var ret = Delete(UrlConfig.CLASSES_DELETECLASSES, data);
46             return int.Parse(ret) == 0;
47         }
48     }
49 }

2. 客户端页面视图

班级管理的客户端页面视图共两个，一个查询列表页面，一个新增编辑页面，共同组成了班级管理的增删改查。

查询班级列表页面，涉及知识点如下所示：

1. 查询条件或者列表中数据列展示，通过数据绑定Binding的方式与ViewModel进行交互，即点击查询按钮，不再传递参数，因为ViewModel中的属性已经同步更新。
2. ViewModel中并非所有属性都可实现双向绑定，必须是实现具有通知功能的属性才可以。在Prism框架中，通过BindableBase的SetProperty方法可以快速实现。
3. View视图中如果控件存在Command命令，则可以直接绑定，如果不存在，则可以i:Interaction.Triggers将事件转换为命令，如Load事件等。
4. 在列表中，如果需要添加按钮，可以通过DataTemplate进行数据定制。

查询班级页面代码，如下所示：

  1 <UserControl x:Class="SIMS.ClassesModule.Views.Classes"
  2              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  3              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  4              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
  5              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  6              xmlns:local="clr-namespace:SIMS.ClassesModule.Views"
  7              xmlns:prism="http://prismlibrary.com/"
  8              xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
  9              xmlns:mahApps="http://metro.mahapps.com/winfx/xaml/controls"
 10              xmlns:ctrls ="clr-namespace:SIMS.Utils.Controls;assembly=SIMS.Utils"
 11              prism:ViewModelLocator.AutoWireViewModel="True"
 12              mc:Ignorable="d" 
 13              d:DesignHeight="450" d:DesignWidth="800">
 14     <UserControl.Resources>
 15         <ResourceDictionary>
 16             <ResourceDictionary.MergedDictionaries>
 17                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
 18                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Themes/Light.Blue.xaml" />
 19                 <ResourceDictionary>
 20                     <Style x:Key="LinkButton" TargetType="Button">
 21                         <Setter Property="Background" Value="White">Setter>
 22                         <Setter Property="Cursor" Value="Hand">Setter>
 23                         <Setter Property="Margin" Value="3">Setter>
 24                         <Setter Property="MinWidth" Value="80">Setter>
 25                         <Setter Property="MinHeight" Value="25">Setter>
 26                         <Setter Property="BorderThickness" Value="0 0 0 0">Setter>
 27                     Style>
 28                 ResourceDictionary>
 29             ResourceDictionary.MergedDictionaries>
 30         ResourceDictionary>
 31     UserControl.Resources>
 32     <i:Interaction.Triggers>
 33         <i:EventTrigger EventName="Loaded">
 34             <i:InvokeCommandAction Command="{Binding LoadedCommand}">i:InvokeCommandAction>
 35         i:EventTrigger>
 36     i:Interaction.Triggers>
 37     <Grid>
 38         <Grid.RowDefinitions>
 39             <RowDefinition Height="Auto">RowDefinition>
 40             <RowDefinition Height="Auto">RowDefinition>
 41             <RowDefinition Height="*">RowDefinition>
 42             <RowDefinition Height="Auto">RowDefinition>
 43         Grid.RowDefinitions>
 44         <TextBlock Text="班级信息" FontSize="20" Background="AliceBlue" Margin="2">TextBlock>
 45         <StackPanel Grid.Row="1" Orientation="Horizontal" VerticalAlignment="Center">
 46             <TextBlock Text="专业" VerticalAlignment="Center" Margin="2">TextBlock>
 47             <TextBox Margin="4" MinWidth="120" Height="30"
 48                      Text="{Binding Dept}"
 49                              HorizontalContentAlignment="Stretch"
 50                              mahApps:TextBoxHelper.ClearTextButton="True"
 51                              mahApps:TextBoxHelper.Watermark="专业"
 52                              mahApps:TextBoxHelper.WatermarkAlignment="Left"
 53                              SpellCheck.IsEnabled="True" />
 54             <TextBlock Text="年级" VerticalAlignment="Center" Margin="2">TextBlock>
 55             <TextBox Margin="4" MinWidth="120" Height="30"
 56                      Text="{Binding Grade}"
 57                              HorizontalContentAlignment="Stretch"
 58                              mahApps:TextBoxHelper.ClearTextButton="True"
 59                              mahApps:TextBoxHelper.Watermark="年级"
 60                              mahApps:TextBoxHelper.WatermarkAlignment="Left"
 61                              SpellCheck.IsEnabled="True" />
 62             <Button Content="查询" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Width="120" Height="30" Margin="3" Command="{Binding QueryCommand}">Button>
 63             <Button Content="新增" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Width="120" Height="30" Margin="3" Command="{Binding AddCommand}">Button>
 64         StackPanel>
 65         <DataGrid x:Name="dgClasses"
 66                   Grid.Row="2"
 67                   Grid.Column="0"
 68                   Margin="2"
 69                   AutoGenerateColumns="False"
 70                   CanUserAddRows="False"
 71                   CanUserDeleteRows="False"
 72                   ItemsSource="{Binding Classes}"
 73                   RowHeaderWidth="0">
 74             <DataGrid.Columns>
 75                 <DataGridTextColumn Binding="{Binding Dept}" Header="专业" Width="*" />
 76                 <DataGridTextColumn Binding="{Binding Grade}" Header="年级" Width="*"/>
 77                 <DataGridTextColumn Binding="{Binding Name}" Header="班级" Width="*"/>
 78                 <DataGridTextColumn Binding="{Binding HeadTeacher}" Header="班主任" Width="*"/>
 79                 <DataGridTextColumn Binding="{Binding MonitorName}" Header="班长" Width="*" />
 80                 <DataGridTemplateColumn Header="操作" Width="*">
 81                     <DataGridTemplateColumn.CellTemplate>
 82                         <DataTemplate>
 83                             <StackPanel Orientation="Horizontal">
 84                                 <Button  Content="Edit" Style="{StaticResource LinkButton}" Command="{Binding RelativeSource={RelativeSource  AncestorType=DataGrid,  Mode=FindAncestor}, Path=DataContext.EditCommand}" CommandParameter="{Binding Id}">
 85                                     <Button.Template>
 86                                         <ControlTemplate TargetType="Button">
 87                                             <TextBlock TextDecorations="Underline" HorizontalAlignment="Center">
 88                                                 <ContentPresenter />
 89                                             TextBlock>
 90                                         ControlTemplate>
 91                                     Button.Template>
 92                                 Button>
 93                                 <Button Content="Delete" Style="{StaticResource LinkButton}" Command="{Binding RelativeSource={RelativeSource  AncestorType=DataGrid,  Mode=FindAncestor}, Path=DataContext.DeleteCommand}" CommandParameter="{Binding Id}">
 94                                     <Button.Template>
 95                                         <ControlTemplate TargetType="Button">
 96                                             <TextBlock TextDecorations="Underline" HorizontalAlignment="Center">
 97                                                 <ContentPresenter />
 98                                             TextBlock>
 99                                         ControlTemplate>
100                                     Button.Template>
101                                 Button>
102                             StackPanel>
103                         DataTemplate>
104                     DataGridTemplateColumn.CellTemplate>
105                 DataGridTemplateColumn>
106             DataGrid.Columns>
107         DataGrid>
108         <ctrls:PageControl Grid.Row="3" DataContext="{Binding}" >ctrls:PageControl>
109     Grid>
110 UserControl>

新增编辑页面

班级的新增功能和编辑功能，共用一个页面，涉及知识点如下所示：

1. 在新增编辑的ViewModel中，班级实体是一个属性，所以在视图控件中进行数据绑定时，需要带上属性名，如：Classes.Name 。
2. 班长列表在新增班级时尚无对应学生，可为空，待维护学生后，可通过学生列表进行选择即可。
3. 班长列表为Combox下拉框，绑定的是学生实体列表，但客户端只需看到学生姓名即可，所以需要重写DataTemplate，只显示学生姓名。

新增班级信息视图，具体代码如下所示：

 1 <UserControl x:Class="SIMS.ClassesModule.Views.AddEditClasses"
 2              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 3              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 4              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
 5              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
 6              xmlns:local="clr-namespace:SIMS.ClassesModule.Views"
 7              mc:Ignorable="d"
 8              xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
 9              xmlns:mahApps ="http://metro.mahapps.com/winfx/xaml/controls"
10              xmlns:prism="http://prismlibrary.com/"      
11              d:DesignHeight="400" d:DesignWidth="600">
12     <prism:Dialog.WindowStyle>
13         <Style TargetType="Window">
14             <Setter Property="Width" Value="600">Setter>
15             <Setter Property="Height" Value="400">Setter>
16         Style>
17     prism:Dialog.WindowStyle>
18     <UserControl.Resources>
19         <ResourceDictionary>
20             <ResourceDictionary.MergedDictionaries>
21                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
22                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Themes/Light.Blue.xaml" />
23             ResourceDictionary.MergedDictionaries>
24         ResourceDictionary>
25     UserControl.Resources>
26     <i:Interaction.Triggers>
27         <i:EventTrigger EventName="Loaded">
28             <i:InvokeCommandAction Command="{Binding LoadedCommand}">i:InvokeCommandAction>
29         i:EventTrigger>
30     i:Interaction.Triggers>
31     <Grid>
32         <Grid.ColumnDefinitions>
33             <ColumnDefinition Width="0.2*">ColumnDefinition>
34             <ColumnDefinition Width="Auto">ColumnDefinition>
35             <ColumnDefinition Width="*">ColumnDefinition>
36             <ColumnDefinition Width="0.2*">ColumnDefinition>
37         Grid.ColumnDefinitions>
38         <Grid.RowDefinitions>
39             <RowDefinition>RowDefinition>
40             <RowDefinition>RowDefinition>
41             <RowDefinition>RowDefinition>
42             <RowDefinition>RowDefinition>
43             <RowDefinition>RowDefinition>
44             <RowDefinition>RowDefinition>
45             <RowDefinition>RowDefinition>
46         Grid.RowDefinitions>
47 
48 
49         <TextBlock Text="专业" Grid.Row="0" Grid.Column="1" VerticalAlignment="Center" Margin="3">TextBlock>
50         <TextBox Grid.Row="0" Grid.Column="2" MinWidth="120" Height="35"  VerticalAlignment="Center" Margin="3" Text="{Binding Classes.Dept}">TextBox>
51         <TextBlock Text="年级" Grid.Row="1" Grid.Column="1"  VerticalAlignment="Center" Margin="3">TextBlock>
52         <TextBox Grid.Row="1" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Classes.Grade}">TextBox>
53         <TextBlock Text="班级" Grid.Row="2" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
54         <TextBox Grid.Row="2" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Classes.Name}">TextBox>
55         <TextBlock Text="班主任" Grid.Row="3" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
56         <TextBox Grid.Row="3" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Classes.HeadTeacher}">TextBox>
57         <TextBlock Text="班长" Grid.Row="4" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
58         <ComboBox Grid.Row="4" Grid.Column="2" MinWidth="120" Height="35" ItemsSource="{Binding Monitors}" mahApps:TextBoxHelper.ClearTextButton="True" SelectedItem="{Binding Monitor}">
59             <ComboBox.ItemTemplate>
60                 <DataTemplate>
61                     <TextBlock Text="{Binding Name}">TextBlock>
62                 DataTemplate>
63             ComboBox.ItemTemplate>
64         ComboBox>
65         <StackPanel Grid.Row="5" Grid.Column="1" Grid.ColumnSpan="2" Orientation="Horizontal" HorizontalAlignment="Center" Margin="3">
66             <Button Content="取消" Margin="5" MinWidth="120" Height="35" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Command="{Binding CancelCommand}">Button>
67             <Button Content="保存" Margin="5" MinWidth="120" Height="35" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Command="{Binding SaveCommand}">Button>
68         StackPanel>
69         <TextBlock Grid.Row="6" Grid.Column="1" Grid.ColumnSpan="2" Text="注意：新增班级时，班长可空，等维护学生后，再设置班长。" Foreground="Red">TextBlock>
70     Grid>
71 UserControl>

3. 客户端ViewModel

班级管理模块，ViewModel和视图对应，也分为查询列表ViewModel和新增编辑ViewModel，如下所示：

ClassesViewModel页面代码分为三部分：

1. 属性和构造函数，主要用于数据绑定，如查询条件，列表等。所有属性的set赋值时，均采用SetProperty进行赋值。
2. 命令Command，如查询，新增，编辑，删除命令等。所有命令可以定义成DelegateCommand类型。
3. 分页部分，因分页功能代码大同小异，所以此处略去。

ClassesViewModel具体代码如下所示：

  1 namespace SIMS.ClassesModule.ViewModels
  2 {
  3     public class ClassesViewModel :BindableBase
  4     {
  5         #region 属性及构造函数
  6 
  7         /// 

  8         /// 专业
  9         /// 
 10         private string dept;
 11 
 12         public string Dept
 13         {
 14             get { return dept; }
 15             set { SetProperty(ref dept , value); }
 16         }
 17 
 18         /// 

 19         /// 年级
 20         /// 
 21         private string grade;
 22 
 23         public string Grade
 24         {
 25             get { return grade; }
 26             set { SetProperty(ref grade , value); }
 27         }
 28 
 29 
 30 
 31         private ObservableCollection classes;
 32 
 33         public ObservableCollection Classes
 34         {
 35             get { return classes; }
 36             set { SetProperty(ref classes, value); }
 37         }
 38 
 39         private IDialogService dialogService;
 40 
 41         public ClassesViewModel(IDialogService dialogService)
 42         {
 43             this.dialogService = dialogService;
 44             this.pageNum = 1;
 45             this.pageSize = 20;
 46         }
 47 
 48         private void InitInfo()
 49         {
 50             Classes = new ObservableCollection();
 51             var pagedRequst = ClassesHttpUtil.GetClassess(this.Dept,this.Grade, this.pageNum, this.pageSize);
 52             var entities = pagedRequst.items;
 53             Classes.AddRange(entities.Select(r=>new ClassesInfo(r)));
 54             //
 55             this.TotalCount = pagedRequst.count;
 56             this.TotalPage = ((int)Math.Ceiling(this.TotalCount * 1.0 / this.pageSize));
 57         }
 58 
 59         #endregion
 60 
 61         #region 事件
 62 
 63         private DelegateCommand loadedCommand;
 64 
 65         public DelegateCommand LoadedCommand
 66         {
 67             get
 68             {
 69                 if (loadedCommand == null)
 70                 {
 71                     loadedCommand = new DelegateCommand(Loaded);
 72                 }
 73                 return loadedCommand;
 74             }
 75         }
 76 
 77         private void Loaded()
 78         {
 79             InitInfo();
 80         }
 81 
 82         private DelegateCommand queryCommand;
 83 
 84         public DelegateCommand QueryCommand
 85         {
 86             get
 87             {
 88                 if (queryCommand == null)
 89                 {
 90                     queryCommand = new DelegateCommand(Query);
 91                 }
 92                 return queryCommand;
 93             }
 94         }
 95 
 96         private void Query() { 
 97             this.pageNum = 1;
 98             this.InitInfo();
 99         }
100 
101         /// 

102         /// 新增命令
103         /// 
104         private DelegateCommand addCommand;
105 
106         public DelegateCommand AddCommand
107         {
108             get
109             {
110                 if (addCommand == null)
111                 {
112                     addCommand = new DelegateCommand(Add);
113                 }
114                 return addCommand;
115             }
116         }
117 
118         private void Add()
119         {
120             this.dialogService.ShowDialog("addEditClasses",null, AddEditCallBack, "MetroDialogWindow");
121         }
122 
123         private void AddEditCallBack(IDialogResult dialogResult) {
124             if (dialogResult != null && dialogResult.Result == ButtonResult.OK) {
125                 //刷新列表
126                 this.pageNum = 1;
127                 this.InitInfo();
128             }
129         }
130 
131         /// 

132         /// 编辑命令
133         /// 
134         private DelegateCommand<object> editCommand;
135 
136         public DelegateCommand<object> EditCommand
137         {
138             get
139             {
140                 if (editCommand == null)
141                 {
142                     editCommand = new DelegateCommand<object>(Edit);
143                 }
144                 return editCommand;
145             }
146         }
147 
148         private void Edit(object obj)
149         {
150             if (obj == null) {
151                 return;
152             }
153             var Id = int.Parse(obj.ToString());
154             var classes = this.Classes.FirstOrDefault(r => r.Id == Id);
155             if (classes == null)
156             {
157                 MessageBox.Show("无效的班级ID");
158                 return;
159             }
160             if (MessageBoxResult.Yes != MessageBox.Show("Are you sure to delete?", "Confirm", MessageBoxButton.YesNo))
161             {
162                 return;
163             }
164             IDialogParameters dialogParameters = new DialogParameters();
165             dialogParameters.Add("classes",classes);
166             this.dialogService.ShowDialog("addEditClasses", dialogParameters, AddEditCallBack, "MetroDialogWindow");
167         }
168 
169         /// 

170         /// 编辑命令
171         /// 
172         private DelegateCommand<object> deleteCommand;
173 
174         public DelegateCommand<object> DeleteCommand
175         {
176             get
177             {
178                 if (deleteCommand == null)
179                 {
180                     deleteCommand = new DelegateCommand<object>(Delete);
181                 }
182                 return deleteCommand;
183             }
184         }
185 
186         private void Delete(object obj)
187         {
188             if (obj == null)
189             {
190                 return;
191             }
192             var Id = int.Parse(obj.ToString());
193             var classes = this.Classes.FirstOrDefault(r => r.Id == Id);
194             if (classes == null)
195             {
196                 MessageBox.Show("无效的班级ID");
197                 return;
198             }
199             bool flag = ClassesHttpUtil.DeleteClasses(Id);
200             if (flag) {
201                 this.pageNum = 1;
202                 this.InitInfo();
203             }
204         }
205 
206         #endregion
207 
208     }
209 }

AddEditClassesViewModel代码同样分为三部分：

1. 属性和构造函数，主要用于数据绑定，如页面文本框，下拉选择框等。
2. 命令Command，主要用于响应事件，如保存，取消等。
3. 对话框接口，因为新增编辑是以弹出框的形式呈现，所以根据Prism框架的 要求，需要实现IDialogAware接口。

AddEditClassesViewModel具体代码如下所示：

  1 namespace SIMS.ClassesModule.ViewModels
  2 {
  3     public class AddEditClassesViewModel : BindableBase, IDialogAware
  4     {
  5         #region 属性和构造函数
  6 
  7         /// 

  8         /// 班级实体
  9         /// 
 10         private ClassesInfo classes;
 11     
 12         public ClassesInfo Classes
 13         {
 14             get { return classes; }
 15             set { SetProperty(ref classes ,value); }
 16         }
 17 
 18         private List monitors;
 19 
 20         public List Monitors
 21         {
 22             get { return monitors; }
 23             set { SetProperty(ref monitors , value); }
 24         }
 25 
 26         private StudentEntity monitor;
 27 
 28         public StudentEntity Monitor
 29         {
 30             get { return monitor; }
 31             set { SetProperty(ref monitor, value); }
 32         }
 33 
 34         public AddEditClassesViewModel() { 
 35         
 36         }
 37 
 38         #endregion
 39 
 40         #region Command
 41 
 42         private DelegateCommand loadedCommand;
 43 
 44         public DelegateCommand LoadedCommand
 45         {
 46             get
 47             {
 48                 if (loadedCommand == null)
 49                 {
 50                     loadedCommand = new DelegateCommand(Loaded);
 51                 }
 52                 return loadedCommand;
 53             }
 54         }
 55 
 56         private void Loaded()
 57         {
 58             this.Monitors= new List();
 59             if (Classes?.Id>0) { 
 60                 var pagedRequst = StudentHttpUtil.GetStudentsByClasses(Classes.Id);
 61                 var entities = pagedRequst.items;
 62                 Monitors.AddRange(entities);
 63                 //如果有班长，则为班长赋值
 64                 if (Classes.Monitor > 0) { 
 65                     this.Monitor= this.Monitors?.FirstOrDefault(r=>r.Id==Classes.Monitor);
 66                 }
 67             }
 68             
 69         }
 70 
 71         private DelegateCommand cancelCommand;
 72 
 73         public DelegateCommand CancelCommand
 74         {
 75             get
 76             {
 77                 if (cancelCommand == null)
 78                 {
 79                     cancelCommand = new DelegateCommand(Cancel);
 80                 }
 81                 return cancelCommand;
 82             }
 83         }
 84 
 85         private void Cancel()
 86         {
 87             RequestClose?.Invoke((new DialogResult(ButtonResult.Cancel)));
 88         }
 89 
 90         private DelegateCommand  saveCommand;
 91 
 92         public DelegateCommand SaveCommand
 93         {
 94             get
 95             {
 96                 if (saveCommand == null)
 97                 {
 98                     saveCommand = new DelegateCommand(Save);
 99                 }
100                 return saveCommand;
101             }
102         }
103 
104         private void Save() {
105             if (Classes != null) {
106                 Classes.CreateTime = DateTime.Now;
107                 Classes.LastEditTime = DateTime.Now;
108                 if (Monitor != null) {
109                     Classes.Monitor = Monitor.Id;
110                 }
111                 bool flag=false;
112                 if (Classes.Id > 0) {
113                    flag = ClassesHttpUtil.UpdateClasses(Classes);
114                 }
115                 else { 
116                    flag = ClassesHttpUtil.AddClasses(Classes);
117                 }
118                 if (flag)
119                 {
120                     RequestClose?.Invoke((new DialogResult(ButtonResult.OK)));
121                 }
122             }
123         }
124 
125 
126         #endregion
127 
128         #region 对话框
129 
130         public string Title =>  "新增或编辑班级信息";
131 
132         public event Action RequestClose;
133 
134         public bool CanCloseDialog()
135         {
136             return true;
137         }
138 
139         public void OnDialogClosed()
140         {
141             
142         }
143 
144         public void OnDialogOpened(IDialogParameters parameters)
145         {
146             if (parameters != null && parameters.ContainsKey("classes"))
147             {
148                 this.Classes = parameters.GetValue("classes");
149             }
150             else { 
151                 this.Classes = new ClassesInfo();
152             }
153         }
154 
155         #endregion
156 
157     }
158 }

4. 示例截图

班级管理示例截图，如下所示：

学生管理

1. 接口访问类StudentHttpUtil

学生数据表结构和服务接口，在第二篇文章中已有介绍，如有疑问，可前往参考。接口访问类用于封装访问服务端提供的接口。如下所示：

 1 namespace SIMS.Utils.Http
 2 {
 3     /// 

 4     /// 学生类Http访问通用类
 5     /// 
 6     public class StudentHttpUtil:HttpUtil
 7     {
 8         /// 

 9         /// 通过id查询学生信息
10         /// 
11         /// 
12         /// 
13         public static StudentEntity GetStudent(int id)
14         {
15             Dictionary<string, object> data = new Dictionary<string, object>();
16             data["id"] = id;
17             var str = Get(UrlConfig.STUDENT_GETSTUDENT, data);
18             var student = StrToObject(str);
19             return student;
20         }
21 
22         public static PagedRequest GetStudents(string no,string name, int pageNum, int pageSize) {
23             Dictionary<string, object> data = new Dictionary<string, object>();
24             data["no"] = no;
25             data["name"] = name;
26             data["pageNum"] = pageNum;
27             data["pageSize"] = pageSize;
28             var str = Get(UrlConfig.STUDENT_GETSTUDENTS, data);
29             var students = StrToObject>(str);
30             return students;
31         }
32 
33         public static PagedRequest GetStudentsByClasses(int classId)
34         {
35             Dictionary<string, object> data = new Dictionary<string, object>();
36             data["classId"] = classId;
37             var str = Get(UrlConfig.STUDENT_GETSTUDENTSBYCLASSES, data);
38             var students = StrToObject>(str);
39             return students;
40         }
41 
42         public static bool AddStudent(StudentEntity student)
43         {
44             var ret = Post(UrlConfig.STUDENT_ADDSTUDENT, student);
45             return int.Parse(ret) == 0;
46         }
47 
48         public static bool UpdateStudent(StudentEntity student)
49         {
50             var ret = Put(UrlConfig.STUDENT_UPDATESTUDENT, student);
51             return int.Parse(ret) == 0;
52         }
53 
54         public static bool DeleteStudent(int Id)
55         {
56             Dictionary<string, string> data = new Dictionary<string, string>();
57             data["Id"] = Id.ToString();
58             var ret = Delete(UrlConfig.STUDENT_DELETESTUDENT, data);
59             return int.Parse(ret) == 0;
60         }
61     }
62 }

2. 客户端页面视图

学生管理模块的客户端视图页面，也分为两个：学生列表查询，新增编辑学生信息页面。

学生列表查询页面

学生信息列表页面设计知识点，和班级管理差不多，只有一点差异：

1. 在数据库中，性别保存的是bit类型，在C#中，数据类型为bool，但是在列表中需要转换成男或女显示，所以需要用到Converter进行转换。

学生信息查询页面，具体代码如下所示：

  1 <UserControl x:Class="SIMS.StudentModule.Views.Student"
  2       xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  3       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  4       xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
  5       xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  6       xmlns:local="clr-namespace:SIMS.StudentModule.Views"
  7       xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
  8       xmlns:mahApps ="http://metro.mahapps.com/winfx/xaml/controls"
  9       xmlns:prism="http://prismlibrary.com/"      
 10       xmlns:ctrls ="clr-namespace:SIMS.Utils.Controls;assembly=SIMS.Utils"
 11       xmlns:conv="clr-namespace:SIMS.Utils.Converter;assembly=SIMS.Utils"
 12       mc:Ignorable="d" 
 13       prism:ViewModelLocator.AutoWireViewModel="True"
 14       d:DesignHeight="450" d:DesignWidth="800">
 15     
 16     <UserControl.Resources>
 17         <ResourceDictionary>
 18             <ResourceDictionary.MergedDictionaries>
 19                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
 20                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Themes/Light.Blue.xaml" />
 21                 <ResourceDictionary>
 22                     <conv:SexConverter x:Key="SexConverter">conv:SexConverter>
 23                     <Style x:Key="LinkButton" TargetType="Button">
 24                         <Setter Property="Background" Value="White">Setter>
 25                         <Setter Property="Cursor" Value="Hand">Setter>
 26                         <Setter Property="Margin" Value="3">Setter>
 27                         <Setter Property="MinWidth" Value="80">Setter>
 28                         <Setter Property="MinHeight" Value="25">Setter>
 29                         <Setter Property="BorderThickness" Value="0 0 0 0">Setter>
 30                     Style>
 31                 ResourceDictionary>
 32             ResourceDictionary.MergedDictionaries>
 33         ResourceDictionary>
 34     UserControl.Resources>
 35     <i:Interaction.Triggers>
 36         <i:EventTrigger EventName="Loaded">
 37             <i:InvokeCommandAction Command="{Binding LoadedCommand}">i:InvokeCommandAction>
 38         i:EventTrigger>
 39     i:Interaction.Triggers>
 40     <Grid>
 41         <Grid.RowDefinitions>
 42             <RowDefinition Height="Auto">RowDefinition>
 43             <RowDefinition Height="Auto">RowDefinition>
 44             <RowDefinition Height="*">RowDefinition>
 45             <RowDefinition Height="Auto">RowDefinition>
 46         Grid.RowDefinitions>
 47         <TextBlock Text="学生信息" FontSize="20" Background="AliceBlue" Margin="2">TextBlock>
 48         <StackPanel Grid.Row="1" Orientation="Horizontal" VerticalAlignment="Center">
 49             <TextBlock Text="学号" VerticalAlignment="Center" Margin="2">TextBlock>
 50             <TextBox Margin="4" MinWidth="120" Height="30"
 51                      Text="{Binding No}"
 52                              HorizontalContentAlignment="Stretch"
 53                              mahApps:TextBoxHelper.ClearTextButton="True"
 54                              mahApps:TextBoxHelper.Watermark="学号"
 55                              mahApps:TextBoxHelper.WatermarkAlignment="Left"
 56                              SpellCheck.IsEnabled="True" />
 57             <TextBlock Text="姓名" VerticalAlignment="Center" Margin="2">TextBlock>
 58             <TextBox Margin="4" MinWidth="120" Height="30"
 59                      Text="{Binding Name}"
 60                              HorizontalContentAlignment="Stretch"
 61                              mahApps:TextBoxHelper.ClearTextButton="True"
 62                              mahApps:TextBoxHelper.Watermark="学生姓名"
 63                              mahApps:TextBoxHelper.WatermarkAlignment="Left"
 64                              SpellCheck.IsEnabled="True" />
 65             <Button Content="查询" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Width="120" Height="30" Margin="3" Command="{Binding QueryCommand}">Button>
 66             <Button Content="新增" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Width="120" Height="30" Margin="3" Command="{Binding AddCommand}">Button>
 67         StackPanel>
 68         <DataGrid x:Name="dgStudent"
 69                   Grid.Row="2"
 70                   Grid.Column="0"
 71                   Margin="2"
 72                   AutoGenerateColumns="False"
 73                   CanUserAddRows="False"
 74                   CanUserDeleteRows="False"
 75                   ItemsSource="{Binding Students}"
 76                   RowHeaderWidth="0">
 77             <DataGrid.Columns>
 78                 <DataGridTextColumn Binding="{Binding No}" Header="学号" Width="*" />
 79                 <DataGridTextColumn Binding="{Binding Name}" Header="姓名" Width="*"/>
 80                 <DataGridTextColumn Binding="{Binding Age}" Header="年龄" Width="*"/>
 81                 <DataGridTextColumn Binding="{Binding Sex, Converter={StaticResource SexConverter}}" Header="性别" Width="*"/>
 82                 <DataGridTextColumn Binding="{Binding ClassesName}" Header="班级" Width="*" />
 83                 <DataGridTemplateColumn Header="操作" Width="*">
 84                     <DataGridTemplateColumn.CellTemplate>
 85                         <DataTemplate>
 86                             <StackPanel Orientation="Horizontal">
 87                                 <Button Content="Edit" Style="{StaticResource LinkButton}" Command="{Binding RelativeSource={RelativeSource  AncestorType=DataGrid,  Mode=FindAncestor}, Path=DataContext.EditCommand}" CommandParameter="{Binding Id}"  >
 88                                     <Button.Template>
 89                                         <ControlTemplate TargetType="Button">
 90                                             <TextBlock TextDecorations="Underline" HorizontalAlignment="Center">
 91                                                 <ContentPresenter />
 92                                             TextBlock>
 93                                         ControlTemplate>
 94                                     Button.Template>
 95                                 Button>
 96                                 <Button Content="Delete" Style="{StaticResource LinkButton}" Command="{Binding RelativeSource={RelativeSource  AncestorType=DataGrid,  Mode=FindAncestor}, Path=DataContext.DeleteCommand}" CommandParameter="{Binding Id}">
 97                                     <Button.Template>
 98                                         <ControlTemplate TargetType="Button">
 99                                             <TextBlock TextDecorations="Underline" HorizontalAlignment="Center">
100                                                 <ContentPresenter />
101                                             TextBlock>
102                                         ControlTemplate>
103                                     Button.Template>
104                                 Button>
105                             StackPanel>
106                         DataTemplate>
107                     DataGridTemplateColumn.CellTemplate>
108                 DataGridTemplateColumn>
109             DataGrid.Columns>
110         DataGrid>
111         <ctrls:PageControl Grid.Row="3" DataContext="{Binding}" >ctrls:PageControl>
112     Grid>
113 UserControl>

新增编辑页面

新增编辑页面涉及知识点和班级新增页面差不多，仅有一处差异：

1. C#中的bool类型，需要绑定到两个单选按钮上，以表示男，女，所以需要扩展。

新增编辑页面，具体代码如下所示：

 1 <UserControl x:Class="SIMS.StudentModule.Views.AddEditStudent"
 2              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 3              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 4              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
 5              xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
 6              xmlns:local="clr-namespace:SIMS.StudentModule.Views"
 7              xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
 8              xmlns:mahApps ="http://metro.mahapps.com/winfx/xaml/controls"
 9              xmlns:prism="http://prismlibrary.com/"      
10              mc:Ignorable="d" 
11              d:DesignHeight="450" d:DesignWidth="600">
12     <prism:Dialog.WindowStyle>
13         <Style TargetType="Window">
14             <Setter Property="Width" Value="600">Setter>
15             <Setter Property="Height" Value="400">Setter>
16         Style>
17     prism:Dialog.WindowStyle>
18     <UserControl.Resources>
19         <ResourceDictionary>
20             <ResourceDictionary.MergedDictionaries>
21                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Controls.xaml" />
22                 <ResourceDictionary Source="pack://application:,,,/MahApps.Metro;component/Styles/Themes/Light.Blue.xaml" />
23             ResourceDictionary.MergedDictionaries>
24         ResourceDictionary>
25     UserControl.Resources>
26     <i:Interaction.Triggers>
27         <i:EventTrigger EventName="Loaded">
28             <i:InvokeCommandAction Command="{Binding LoadedCommand}">i:InvokeCommandAction>
29         i:EventTrigger>
30     i:Interaction.Triggers>
31     <Grid>
32         <Grid.ColumnDefinitions>
33             <ColumnDefinition Width="0.2*">ColumnDefinition>
34             <ColumnDefinition Width="Auto">ColumnDefinition>
35             <ColumnDefinition Width="*">ColumnDefinition>
36             <ColumnDefinition Width="0.2*">ColumnDefinition>
37         Grid.ColumnDefinitions>
38         <Grid.RowDefinitions>
39             <RowDefinition>RowDefinition>
40             <RowDefinition>RowDefinition>
41             <RowDefinition>RowDefinition>
42             <RowDefinition>RowDefinition>
43             <RowDefinition>RowDefinition>
44             <RowDefinition>RowDefinition>
45         Grid.RowDefinitions>
46 
47 
48         <TextBlock Text="学号" Grid.Row="0" Grid.Column="1" VerticalAlignment="Center" Margin="3">TextBlock>
49         <TextBox Grid.Row="0" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Student.No}">TextBox>
50         <TextBlock Text="姓名" Grid.Row="1" Grid.Column="1"  VerticalAlignment="Center" Margin="3">TextBlock>
51         <TextBox Grid.Row="1" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Student.Name}">TextBox>
52         <TextBlock Text="年龄" Grid.Row="2" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
53         <TextBox Grid.Row="2" Grid.Column="2" MinWidth="120" Height="35"   VerticalAlignment="Center" Margin="3" Text="{Binding Student.Age}">TextBox>
54         <TextBlock Text="性别" Grid.Row="3" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
55         <StackPanel Grid.Row="3" Grid.Column="2" Orientation="Horizontal" >
56             <RadioButton Content="男" IsChecked="{Binding Student.IsBoy}">RadioButton>
57             <RadioButton Content="女" IsChecked="{Binding Student.IsGirl}">RadioButton>
58         StackPanel>
59         
60         <TextBlock Text="班级" Grid.Row="4" Grid.Column="1"   VerticalAlignment="Center" Margin="3">TextBlock>
61         <ComboBox Grid.Row="4" Grid.Column="2" MinWidth="120" Height="35" ItemsSource="{Binding Classess}" mahApps:TextBoxHelper.ClearTextButton="True" SelectedItem="{Binding Classes}">
62             <ComboBox.ItemTemplate>
63                 <DataTemplate>
64                     <StackPanel Orientation="Horizontal">
65                         <TextBlock Text="{Binding Dept}">TextBlock>
66                         <TextBlock Text="{Binding Grade}">TextBlock>
67                         <TextBlock Text="{Binding Name}">TextBlock>
68                     StackPanel>
69                 DataTemplate>
70             ComboBox.ItemTemplate>
71         ComboBox>
72         <StackPanel Grid.Row="5" Grid.Column="1" Grid.ColumnSpan="2" Orientation="Horizontal" HorizontalAlignment="Center" Margin="3">
73             <Button Content="取消" Margin="5" MinWidth="120" Height="35" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Command="{Binding CancelCommand}" >Button>
74             <Button Content="保存" Margin="5" MinWidth="120" Height="35" Style="{DynamicResource MahApps.Styles.Button.Square.Accent}" Command="{Binding SaveCommand}">Button>
75         StackPanel>
76     Grid>
77 UserControl>

3. 客户端ViewModel

学生管理客户端ViewModel，与页面视图对应，也分为两个部分

StudentViewModel代码分为三部分：

1. 属性和构造函数，主要用于数据绑定，如查询条件，列表等。所有属性的set赋值时，均采用SetProperty进行赋值。
2. 命令Command，如查询，新增，编辑，删除命令等。所有命令可以定义成DelegateCommand类型。
3. 分页部分，因分页功能代码大同小异，所以此处略去。

StudentViewModel具体代码如下所示：

  1 namespace SIMS.StudentModule.ViewModels
  2 {
  3     public class StudentViewModel:BindableBase
  4     {
  5         #region 属性及构造函数
  6 
  7         /// 

  8         /// 学号
  9         /// 
 10         private string no;
 11 
 12         public string No
 13         {
 14             get { return no; }
 15             set { SetProperty(ref no , value); }
 16         }
 17 
 18         /// 

 19         /// 学生姓名
 20         /// 
 21         private string name;
 22 
 23         public string Name
 24         {
 25             get { return name; }
 26             set { SetProperty(ref name, value); }
 27         }
 28 
 29         private ObservableCollection students;
 30 
 31         public ObservableCollection Students
 32         {
 33             get { return students; }
 34             set { SetProperty(ref students, value); }
 35         }
 36 
 37         private IDialogService dialogService;
 38 
 39         public StudentViewModel(IDialogService dialogService) {
 40             this.dialogService = dialogService;
 41             this.pageNum = 1;
 42             this.pageSize = 20;
 43         }
 44 
 45         private void InitInfo() {
 46             Students = new ObservableCollection();
 47             var pagedRequst = StudentHttpUtil.GetStudents(this.No,this.Name, this.pageNum, this.pageSize);
 48             var entities = pagedRequst.items;
 49             Students.AddRange(entities.Select(r=>new StudentInfo(r)));
 50             //
 51             this.TotalCount = pagedRequst.count;
 52             this.TotalPage=((int)Math.Ceiling(this.TotalCount*1.0/this.pageSize));
 53         }
 54 
 55         #endregion
 56 
 57         #region 事件
 58 
 59         private DelegateCommand loadedCommand;
 60 
 61         public DelegateCommand LoadedCommand
 62         {
 63             get
 64             {
 65                 if (loadedCommand == null)
 66                 {
 67                     loadedCommand = new DelegateCommand(Loaded);
 68                 }
 69                 return loadedCommand;
 70             }
 71         }
 72 
 73         private void Loaded()
 74         {
 75             InitInfo();
 76         }
 77 
 78         /// 

 79         /// 新增命令
 80         /// 
 81         private DelegateCommand addCommand;
 82 
 83         public DelegateCommand AddCommand
 84         {
 85             get
 86             {
 87                 if (addCommand == null)
 88                 {
 89                     addCommand = new DelegateCommand(Add);
 90                 }
 91                 return addCommand;
 92             }
 93         }
 94 
 95         private void Add()
 96         {
 97             this.dialogService.ShowDialog("addEditStudent", null, AddEditCallBack, "MetroDialogWindow");
 98         }
 99 
100         private void AddEditCallBack(IDialogResult dialogResult)
101         {
102             if (dialogResult != null && dialogResult.Result == ButtonResult.OK)
103             {
104                 //刷新列表
105                 this.pageNum = 1;
106                 this.InitInfo();
107             }
108         }
109 
110         /// 

111         /// 编辑命令
112         /// 
113         private DelegateCommand<object> editCommand;
114 
115         public DelegateCommand<object> EditCommand
116         {
117             get
118             {
119                 if (editCommand == null)
120                 {
121                     editCommand = new DelegateCommand<object>(Edit);
122                 }
123                 return editCommand;
124             }
125         }
126 
127         private void Edit(object obj) {
128             if (obj == null)
129             {
130                 return;
131             }
132             var Id = int.Parse(obj.ToString());
133             var student = this.Students.FirstOrDefault(r => r.Id == Id);
134             if (student == null)
135             {
136                 MessageBox.Show("无效的学生ID");
137                 return;
138             }
139             if (MessageBoxResult.Yes != MessageBox.Show("Are you sure to delete?", "Confirm", MessageBoxButton.YesNo))
140             {
141                 return;
142             }
143             IDialogParameters dialogParameters = new DialogParameters();
144             dialogParameters.Add("student", student);
145             this.dialogService.ShowDialog("addEditStudent", dialogParameters, AddEditCallBack, "MetroDialogWindow");
146         }
147 
148         /// 

149         /// 编辑命令
150         /// 
151         private DelegateCommand<object> deleteCommand;
152 
153         public DelegateCommand<object> DeleteCommand
154         {
155             get
156             {
157                 if (deleteCommand == null)
158                 {
159                     deleteCommand = new DelegateCommand<object>(Delete);
160                 }
161                 return deleteCommand;
162             }
163         }
164 
165         private void Delete(object obj)
166         {
167             if (obj == null)
168             {
169                 return;
170             }
171             var Id = int.Parse(obj.ToString());
172             var classes = this.Students.FirstOrDefault(r => r.Id == Id);
173             if (classes == null)
174             {
175                 MessageBox.Show("无效的学生ID");
176                 return;
177             }
178             bool flag = StudentHttpUtil.DeleteStudent(Id);
179             if (flag)
180             {
181                 this.pageNum = 1;
182                 this.InitInfo();
183             }
184         }
185 
186         #endregion
187 
188     }
189 }

AddEditStudentViewModel代码同样分为三部分：

1. 属性和构造函数，主要用于数据绑定，如页面文本框，下拉选择框等。
2. 命令Command，主要用于响应事件，如保存，取消等。
3. 对话框接口，因为新增编辑是以弹出框的形式呈现，所以根据Prism框架的 要求，需要实现IDialogAware接口。(实现接口代码大同小异，在此略去)

AddEditStudentViewModel具体代码如下所示：

  1 namespace SIMS.StudentModule.ViewModels
  2 {
  3     public class AddEditStudentViewModel : BindableBase, IDialogAware
  4     {
  5 
  6         /// 

  7         /// 班级实体
  8         /// 
  9         private ClassesEntity classes;
 10 
 11         public ClassesEntity Classes
 12         {
 13             get { return classes; }
 14             set { SetProperty(ref classes, value); }
 15         }
 16 
 17         /// 

 18         /// 班级列表
 19         /// 
 20         private List classess;
 21 
 22         public List Classess
 23         {
 24             get { return classess; }
 25             set { SetProperty(ref classess, value); }
 26         }
 27 
 28         private StudentInfo student;
 29 
 30         public StudentInfo Student
 31         {
 32             get { return student; }
 33             set { student = value; }
 34         }
 35 
 36         public AddEditStudentViewModel() { 
 37         
 38         }
 39 
 40         #region Command
 41 
 42         private DelegateCommand loadedCommand;
 43 
 44         public DelegateCommand LoadedCommand
 45         {
 46             get
 47             {
 48                 if (loadedCommand == null)
 49                 {
 50                     loadedCommand = new DelegateCommand(Loaded);
 51                 }
 52                 return loadedCommand;
 53             }
 54         }
 55 
 56         private void Loaded()
 57         {
 58             this.Classess = new List();
 59             var pagedRequst = ClassesHttpUtil.GetClassess(null,null,1,0);//0表示所有班级
 60             var entities = pagedRequst.items;
 61             Classess.AddRange(entities);
 62         }
 63 
 64         private DelegateCommand cancelCommand;
 65 
 66         public DelegateCommand CancelCommand
 67         {
 68             get
 69             {
 70                 if (cancelCommand == null)
 71                 {
 72                     cancelCommand = new DelegateCommand(Cancel);
 73                 }
 74                 return cancelCommand;
 75             }
 76         }
 77 
 78         private void Cancel() {
 79             RequestClose?.Invoke((new DialogResult(ButtonResult.Cancel)));
 80         }
 81 
 82         private DelegateCommand saveCommand;
 83 
 84         public DelegateCommand SaveCommand
 85         {
 86             get
 87             {
 88                 if (saveCommand == null)
 89                 {
 90                     saveCommand = new DelegateCommand(Save);
 91                 }
 92                 return saveCommand;
 93             }
 94         }
 95 
 96         private void Save()
 97         {
 98             if (Student != null)
 99             {
100                 Student.CreateTime = DateTime.Now;
101                 Student.LastEditTime = DateTime.Now;
102                 bool flag = false;
103                 if (Classes != null) { 
104                     Student.ClassesId = Classes.Id;
105                 }
106                 if (Student.Id > 0)
107                 {
108                     flag = StudentHttpUtil.UpdateStudent(Student);
109                 }
110                 else
111                 {
112                     flag = StudentHttpUtil.AddStudent(Student);
113                 }
114                 if (flag)
115                 {
116                     RequestClose?.Invoke((new DialogResult(ButtonResult.OK)));
117                 }
118             }
119         }
120 
121         #endregion
122     }
123 }

4. 示例截图

学生管理示例截图，如下所示：

总结

通过本篇文章的班级管理模块，学生管理模块，以及上一篇文章中的课程管理模块，不难发现，每一个模块的开发都是由列表DataGrid，文本框TextBox，下拉框Combox，单选按钮RadioButton，按钮Button等组成的，虽功能略有差异，但总归万变不离其宗。开发方法也大同小异，复杂的功能都是普通的功能累加起来的。这也是本系列文章由浅入深的渐进安排。希望能够抛砖引玉，不局限于某一功能，而是能够举一反三，自我理解，以达到自我开发的能力。