Question

我提供了一项提供数据的服务。当我直接返回数据时，它可以工作：

When I return directly the data, it works. Like that :

 return [
            {
                "prop1": "value1",
                "prop2": "value2"  
            },
            {
                "prop1": "value3",
                "prop2": "value6"
            }
        ];

但是当我尝试从JSON文件中获取它们时，它不会：

// Get Data from JSON
private _getDataFromJson(url: string) {
    return this.http.get(url)
               .toPromise()
               .then(res => res.json())
               .then(data => { return data; })
}
// I also tested that
/*return this.http.get(this._generateUrl(type, 'column-def'))
             .map(res => res.json());*/

我正在将这些json文件数据用于ag网格（默认colDef，colDef，floatingTopRows和datasource）。我不确定它是否相关。

我的代码看起来像这样：

ngOnInit() {
    this.defaultColDef = this.FakeData.getColumnDefDefault();
    this.colDef = this.FakeData.getColumnDef(this.dataType);
    this.floatingTopRowData =  this.FakeData.getFloatingTopRows(this.dataType);
    this.allOfTheData = this.FakeData.getData(this.dataType);

    this.gridOptions = <GridOptions> {
            onGridReady: () => {
                this._populateData();
            }
    };
}

其他相关方法：

_populateData(): void {
    this.allOfTheData.then(rowData => {
        this._setRowData(rowData);
        this.pageSizes = this._generatePageSizes(rowData.length);
    });
}

_setRowData(rowData): void {
    this.allOfTheData = rowData;
    this._createNewDatasource();
}

_createNewDatasource(): void {
    if(!this.allOfTheData) return;

    let dataSource = {
        getRows: (params: any) => {
            this.sortedAndFilteredData = this._sortAndFilter(params.sortModel, params.filterModel);
            let rowsThisPage = this.sortedAndFilteredData.slice(params.startRow, params.endRow);
            params.successCallback(rowsThisPage, this.sortedAndFilteredData.length);
        }
    };

    this.gridOptions.api.setDatasource(dataSource);
}

修改

我的模板：

<ag-grid-ng2 #agGrid [id]="id" style="width: 100%;" [style.height.px]="gridHeight" class="ag-bootstrap" (modelUpdated)="setHeight()"
[gridOptions]="gridOptions"
[defaultColDef]="defaultColDef"
[columnDefs]="colDef"
[floatingTopRowData]="floatingTopRowData"
enableColResize
enableServerSideSorting
enableServerSideFilter
suppressDragLeaveHidesColumns
suppressMultiSort
rowModelType="pagination"
[headerHeight]="headerHeight"
[rowHeight]="rowHeight" 
rowSelection="multiple"
(dragStopped)="_onColumnMoved()"
(selectionChanged)="_onSelectionChanged()">

提前致谢。

Answer 1

private _getDataFromJson(url: string) {
    return this.http.get(url)
           .toPromise()
           .then(res => res.json())
           .then(data => { return data; })
}

此方法返回一个promise，因此，调用方法需要使用promise来获取数据。

所以调用_getDataFromJson(url)看起来像这样：

this._getDataFromJson(someUrl).then(data => this.foo = data);

或者因为你正在使用Typescript，你可以使用async / await：

this.foo = await this._getDataFromJson(someUrl);  // don't forget the async keyword on the enclosing method

Angular 2：异步数据问题

1 个答案: