Javascript DevExpress的DevExtreme用于Angular2和预选

我正在使用DevXpress的DevExtreme和Angular2。我在下面有一个数据网格，列出了状态，并要求用户选择一些状态。有些状态可能已经存储在数据库中。如何设置以前选择的状态？我在文档中看到，我应该使用dataGrid.instance.SelectRowsarrayofPreouslySelectedStates，但dataGrid是在我尝试在ngOnInit中设置后实例化的

我的HTML网格：

<dx-data-grid #statesGrid id="statesContainer" [dataSource]="states" [selectedRowKeys]="[]" [hoverStateEnabled]="true" [showBorders]="true" [showColumnLines]="true" [showRowLines]="true" [rowAlternationEnabled]="true">
    <dxo-sorting mode="multiple"></dxo-sorting>
    <dxo-selection mode="multiple" [deferred]="true"></dxo-selection>
    <dxo-paging [pageSize]="10"></dxo-paging>
    <dxo-pager [showPageSizeSelector]="true" [allowedPageSizes]="[5, 10, 20]" [showInfo]="true"></dxo-pager>
    <dxo-filter-row [visible]="true"></dxo-filter-row>
    <dxi-column dataField="abbreviation" [width]="100"></dxi-column>
    <dxi-column dataField="name"></dxi-column>
</dx-data-grid>

我的组件：

import 'rxjs/add/operator/switchMap';
import { Component, OnInit, ViewContainerRef, ViewChild } from '@angular/core';
import { CompanyService } from './../../../shared/services/company.service';
import { StateService } from './../../../shared/services/state.service';
import notify from 'devextreme/ui/notify';
import { DxDataGridModule, DxDataGridComponent } from 'devextreme-angular';

@Component({
  selector: 'app-company-detail',
  templateUrl: './company-detail.component.html'
})
export class CompanyDetailComponent implements OnInit {
  @ViewChild(DxDataGridComponent) dataGrid: DxDataGridComponent;

  companyStates: Array<ICompanyState>;
  states: Array<IState>;

  constructor(private CompanyService: CompanyService, private StateService: StateService) { }

  ngOnInit() {
    this.StateService.getStates().subscribe((states) => {
        this.getSelectedStates();
        this.states = states
    });
  }

  public getSelectedStates = (): void => {
      this.CompanyService.getStates(id).subscribe((states) => {
        let preselectedStates: Array<IState> = this.companyStates.map((state) => {
            return { abbreviation: state.Abbreviation, name: state.Name }
        });

        // I get an error here that says that dataGrid is undefined.
        this.dataGrid.instance.selectRows(preselectedStates, false);
      }
  }
}

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感谢@yurzui的评论，我能够用以下方式解决我的问题。[selectedRowKeys]处理所有预选。它的问题是，当进行其他选择时，它不会自动更新。因此，我监听了onSelectionChanged，并将事件传递到我的自定义函数中，该函数更新selectedStates，然后在单击save按钮时将数据保存到数据库中

从数据库中获取预选状态

public getCompanyStates = (): void => {
    this.CompanyService.getStates().subscribe((states) => {
        this.selectedStates = states;
    });
}

事件处理程序

public onSelectionChanged = (e): void => {
    this.selectedStates = e.selectedRowKeys;
}

HTML的dx数据网格部分

<dx-data-grid #statesGrid id="statesContainer" 
    (onSelectionChanged)="onSelectionChanged($event)" 
    [selectedRowKeys]="selectedStates"
    [dataSource]="states">
    ...
</dx-data-grid>

---

为什么不想使用selectedRowKeys？非常感谢。正是这一点最终帮助了我，尽管这不是完整的答案。selectedRowKeys有点误导人，但一旦我理解了它，我就能够让它全部正常工作。