Question

有一个代码：

<select name="department" class="form-control select" [(ngModel)]="departments" formControlName="departmentControl">    
    <option *ngFor="let department of departments" [ngValue]="department" [selected]="department.id == this.departmentid">
      {{ department.name }}
    </option>
  </select>

和功能：

isSelected(department): boolean {
  debugger;
  return department.id == this.departmentid;
}

department - 是用户详细信息组件的嵌套组件。在我第一次选择用户详细信息组件后，未选择部门。但第二次一切正常。哪里出错？

Answer 1

您正在使用[selected]="department.id == this.departmentid"

时无需：[(ngModel)]

将[(ngModel)]="departments"更改为[(ngModel)]="departmentid"

将[ngValue]="department"更改为[ngValue]="department.id"

最后看起来应该是这样的：

<select name="department" class="form-control select" [(ngModel)]="departmentid" formControlName="departmentControl">    
    <option *ngFor="let department of departments" [ngValue]="department.id" >
        {{ department.name }}
    </option>
</select>

<强> WORKING DEMO

Answer 2

您的ngModel错误，您应该将其departmentid设置为ngValue，<select name="department" class="form-control select" [(ngModel)]="departmentid" formControlName="departmentControl"> <option *ngFor="let department of departments" [ngValue]="department.id" [selected]="department.id == this.departmentid"> {{ department.name }} </option> </select>应该是部门的ID，如下所示

TcpClient client = new TcpClient();

client.Connect(resolvedIpAddr, PORT_TLS_11);

Org.BouncyCastle.Security.SecureRandom sr = new Org.BouncyCastle.Security.SecureRandom(); 
TlsProtocolHandler handler = new TlsProtocolHandler(client.GetStream(), sr);

handler.Connect(new MyTlsClient());

有关详情，请参阅 answer

Angular4：第一次选择[selected]不起作用

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