与formarray的角度拖动



我有2个数组。我正在实现一个角度拖动,我想使用formarray来保存将元素滴入其中的数组。

问题是我不能将FormControl应用于DIV,因为它给出了一个错误

错误:没有名称的形式控件的值登录器:'语言'

这是HTML

      <div>
        <div class="example-container">
          <h2>Selected Languages</h2>
          <div
          cdkDropList
          #todoList="cdkDropList"
          [cdkDropListData]="anotherarray"
          [cdkDropListConnectedTo]="[doneList]"
          class="example-list"
          (cdkDropListDropped)="drop($event)"
           formControlName="language">
          <div class="list-group-item list-group-item-action " *ngFor="let item of anotherarray" cdkDrag>
            {{item}}
          </div>
        </div>
      </div>
      <div class="example-container">
        <h2>Available Languages</h2>
        <div
        cdkDropList
        #doneList="cdkDropList"
        [cdkDropListData]="testingarray"
        [cdkDropListConnectedTo]="[todoList]"
        class="example-list"
        (cdkDropListDropped)="drop($event)">
        <div class="list-group-item list-group-item-action " *ngFor="let item of testingarray" cdkDrag>{{item}}</div>
      </div>
      </div>
      </div>
      <button type="submit" class="btn btn-primary my-2" translate>saveButtonLabel
        <fa-icon *ngIf="saveIcon" [icon]="saveIcon" [spin]="saveIcon.iconName === 'spinner'"></fa-icon>
      </button>
    </form>
如下

这仅支持常规数组,但是根据Piernik在Stackoverflow上的答案,您可以通过以下功能复制formarray的功能:

import { FormArray } from '@angular/forms';
/**
 * Moves an item in a FormArray to another position.
 * @param formArray FormArray instance in which to move the item.
 * @param fromIndex Starting index of the item.
 * @param toIndex Index to which he item should be moved.
 */
export function moveItemInFormArray(
  formArray: FormArray,
  fromIndex: number,
  toIndex: number
): void {
  const dir = toIndex > fromIndex ? 1 : -1;
  const item = formArray.at(fromIndex);
  for (let i = fromIndex; i * dir < toIndex * dir; i = i + dir) {
    const current = formArray.at(i + dir);
    formArray.setControl(i, current);
  }
  formArray.setControl(toIndex, item);
}

然后,在您的调用代码中,您通过formarray代替普通数组。

get formControls(): FormArray {
    return this.form.get('arrayName') as FormArray;
}
constructor() {
    this.form = this.formBuilder.group({
      arrayName: this.formBuilder.array([]),
    });
}
drop(event: CdkDragDrop<string[]>) {
    moveItemInFormArray(
      this.formControls,
      event.previousIndex,
      event.currentIndex
    );
  }

请参阅此处的工作stackblitz

当前,我们无法使用具有角拖动的FormControl,因为它可以与DIV一起使用,因此我们无法在其上添加FormContol。因此,我们需要使用事件CDKDROPLISTOPPORDED进行,每次删除项目时都会手动更新我们的模型。

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