echarts呈现数据表图形

讲一下echarts的用法，列举了两个图表，一个是单柱图，一个是多柱图，至于饼状图，只许更改echarts的类型就好了

　　一、首先是要两个div，用来存放两个图表

　　<div class="div-frm" style="height: 275px; font-family: Microsoft YaHei, Verdana, Arial;">
        <div id="barone" style="width: 100%; height: 240px; float: left; font-family: Microsoft YaHei, Verdana, Arial;">div>
    div>

    <div style="height: 240px; font-family: Microsoft YaHei, Verdana, Arial;">
        <div id="barthree" class="chart-container" style="width: 100%; height: 240px; float: left; font-family: Microsoft YaHei, Verdana, Arial;">div>
    div>

　　二、需要用js从后台获取json数据（可以从cs页面获取，也可以通过一般处理程序，这里用的一般处理程序）

<%--单个柱状图--%>
    

    <%-- 多个柱状图 --%>
    

　　三、在后台，从数据库读取数据

        static string conStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        JavaScriptSerializer jsS = new JavaScriptSerializer();
        List<object> seriesList = new List<object>();
        List<string> xAxisList = new List<string>();
        string result = "";

        public void ProcessRequest(HttpContext context)
        {
            string command = context.Request["type"];

            switch (command)
            {
                case "bar":
                    GetOverView(context);
                    break;
            };
        }

        public void GetOverView(HttpContext context)
        {
            using (SqlConnection conn = new SqlConnection())
            {
                conn.ConnectionString = conStr;
                conn.Open();

                string sql = "select * from Achievement";
                SqlDataAdapter myda = new SqlDataAdapter(sql, conStr);
                DataTable dt = new DataTable(); // 实例化数据表
                myda.Fill(dt); // 保存数据 

                foreach (DataRow dr in dt.Rows)
                {
                    xAxisList.Add(dr["Name"].ToString());
                    seriesList.Add(dr["Math"].ToString());
                }

                var newObj = new
                {
                    xAxis = xAxisList,
                    series = seriesList
                };

                jsS = new JavaScriptSerializer();
                result = jsS.Serialize(newObj);
                context.Response.Write(result);

                conn.Close(); // 关闭数据库连接
            }
        }    

        static string conStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        JavaScriptSerializer jsS = new JavaScriptSerializer();
        List<object> seriesList = new List<object>();
        List<string> xAxisList = new List<string>();
        List<string> legendList = new List<string>();
        string result = "";

        public void ProcessRequest(HttpContext context)
        {
            string command = context.Request["type"];

            switch (command)
            {
                case "bar":
                    GetOverView(context);
                    break;
            };
        }

        public void GetOverView(HttpContext context)
        {

            using (SqlConnection conn = new SqlConnection())
            {
                conn.ConnectionString = conStr;
                conn.Open();

                string sql = "select * from Achievement";
                SqlDataAdapter myda = new SqlDataAdapter(sql, conStr);
                DataTable dt = new DataTable(); // 实例化数据表
                myda.Fill(dt); // 保存数据 


                legendList.Add("数学");
                legendList.Add("语文");
                legendList.Add("英语");

                //设置对应的Series信息
                Series UVSeriesObj = new Series();
                UVSeriesObj.name = "数学";
                UVSeriesObj.type = "bar"; //图呈现  
                UVSeriesObj.data = new List<object>();

                Series UIPSeriesObj = new Series();
                UIPSeriesObj.name = "语文";
                UIPSeriesObj.type = "bar"; //图呈现  
                UIPSeriesObj.data = new List<object>();

                Series PVSeriesObj = new Series();
                PVSeriesObj.name = "英语";
                PVSeriesObj.type = "bar"; //图呈现  
                PVSeriesObj.data = new List<object>();

                foreach (DataRow dr in dt.Rows)
                {
                    xAxisList.Add(dr["Name"].ToString());

                    UVSeriesObj.data.Add(dr["Math"]);
                    UIPSeriesObj.data.Add(dr["Chinese"]);
                    PVSeriesObj.data.Add(dr["English"]);
                }

                seriesList.Add(UVSeriesObj);
                seriesList.Add(UIPSeriesObj);
                seriesList.Add(PVSeriesObj);

                var newObj = new
                {
                    legend = legendList,    //三门学科
                    xAxis = xAxisList,
                    series = seriesList
                };

                jsS = new JavaScriptSerializer();
                result = jsS.Serialize(newObj);
                context.Response.Write(result);
            }
        }


        public bool IsReusable
        {
            get
            {
                return false;
            }
        }


        class Series
        {
            /// 
  
            /// series序列组名称  
            ///   
            public string name
            {
                get;
                set;
            }

            /// 
  
            /// series序列组呈现图表类型(line、column、bar等)  
            ///   
            public string type
            {
                get;
                set;
            }

            /// 
  
            /// series序列组的数据为数据类型数组  
            ///   
            public List<object> data
            {
                get;
                set;
            }
        }        

　　echarts官方api文档：http://echarts.baidu.com/echarts2/doc/example.html