TypeError: def.when is not a function in Angular Material Table

Question

我尝试使用 when 谓词通过 colspan (matColumnDef="table-filter") 获取额外的行。有趣的是，我在应用程序的其他地方（其他模块）使用了相同的原理，并且它工作正常。

<table mat-table [dataSource]="dataSource">

    <ng-container matColumnDef="table-filter">
        <td mat-cell [attr.colspan]="displayedColumns.length" *matCellDef="let data">
            Test
        </td>
    </ng-container>

    <ng-container matColumnDef="some-column">
        <th mat-header-cell *matHeaderCellDef>
            Column-Titel
        </th>
        <td mat-cell *matCellDef="let data">
            {{ data.someField }}
        </td>
    </ng-container>

    <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
    <tr mat-row *matRowDef="let role; columns: displayedColumns;"></tr>

    <!-- Extra row with when predicate -->
    <tr mat-row *matRowDef="let role; columns: ['table-filter']; when testBoolean;"></tr>
</table>

在这里，我得到 TypeError: def.when is not a function。当我删除多余的行时，table 工作正常（MatTableModule 当然是导入的）。

有什么想法吗？

material: ^8.0.2
angular: ^8.1.1

Answer 1

...愚蠢的我，5 分钟。发布后我发现我对 when-predicate 使用了一个布尔值 - 但这需要是一个具有以下签名的函数：

  /**
   * Function that should return true if this row template should be used for the provided index
   * and row data. If left undefined, this row will be considered the default row template to use
   * when no other when functions return true for the data.
   * For every row, there must be at least one when function that passes or an undefined to default.
   */
  when: (index: number, rowData: T) => boolean;

TypeError: def.when is not a function in Angular Material Table

TypeError: def.when is not a function in Angular Material Table

angular

angular-material

angular-material-table