mat-option 存储自定义数据

select  class="mat-select-custom" formControlName="sourceData" (selectionChange)="sourceDataSwitch($event)" required>
                      "">{{ 'PleaseSelect' | translate }}
                      "let item of sourceDataSurveyList" [label]="item['surveyName'][usingLanguage]">
                        "let question of item['questions']" [attr.data-optionsArray]="init(question['optionsArray'])" value="{{question['externalQuestionID']}}#{{question['questionTypeId']}}">
                          {{question['question'][usingLanguage]}}
                        
                      
                    select>

sourceDataSwitch(event)
{
let target=event.source.selected._element.nativeElement.getAttribute('data-optionsArray');
}