angular - ngModel 无法在表单标签内工作

Question

[(ngModel)] 在表单标签内不工作

当我使用 Multi Select Outside Form 标签时，可以正常选择 All 和取消选择所有功能

但是当我把它放入 Form 里面时，它正在工作 Selecting All Values

<form [formGroup]="roleForm">

    <mat-form-field class="example-full-width">
        <mat-select placeholder="Select Role Type" formControlName="roleType" (selectionChange)="roleTypeSelect($event.value)">
            <mat-option *ngFor="let role of roleTypeList" [value]="role.roleTypeId">
                {{role.roleTypeName}}
            </mat-option>
        </mat-select>
    </mat-form-field> <!-- Multi Select Mat Start -->
    <mat-form-field class="example-full-width">

        <mat-select placeholder="Select Privileges" class="filter-select" [formControl]="selectedItems" [compareWith]="equals" multiple
         #privilegeSelect="ngModel">
            <mat-option disabled="disabled" class="filter-option">
                <button mat-raised-button class="mat-primary fill text-sm" (click)="selectAll(privilegeSelect, dropdownList)">
                    Select All
                </button>
                <button mat-raised-button class="mat-primary fill text-sm eta-margin-all" (click)="deselectAll(privilegeSelect)">
                    Deselect All
                </button>
            </mat-option>
            <mat-option *ngFor="let privilege of dropdownList" [value]="privilege">{{privilege.itemName}}</mat-option>
        </mat-select>

    </mat-form-field>
    <!-- Multi select mat end -->

</form>

Answer 1

如果你只使用 ngModel没有周围<form> ，您不必指定 name用于输入。

<input ... [(ngModel)]="model.something"`>

但是当您在表单中使用它时，name属性成为必需的!

<form>
  <input ... name="something" [(ngModel)]="model.something"`>
</form>

它实际上在文档中:

When using the ngModel within tags, you'll also need to supply a name attribute so that the control can be registered with the parent form under that name.

如果您错过了它，它根本不会显示任何错误，它只是无法工作。