toODataString Method Throwing error filterOperators(...) is not a function Kendo Angular答案

【问题标题】：toODataString Method Throwing error filterOperators(...) is not a function Kendo AngulartoODataString Method Throwing error filterOperators(...) is not a function Kendo Angular
【发布时间】：2020-05-28 13:46:06
【问题描述】：

我正在为 Angular 使用 Kendo UI 的过滤器小部件。为了将过滤器表达式转换为 oData 查询，我使用了 toODataQuery 方法并将状态传递给它。

在添加组时我得到了

 filterOperators(...) is not a function
    at odata-filtering.operators.js:69
    at funcs.js:4
    at odata-filtering.operators.js:70
    at Array.map (<anonymous>)

我已经为此创建了 stackblitz：https://stackblitz.com/edit/angular-ivy-gny5pv?file=src%2Fapp%2Fapp.component.ts

我能够重现错误，但错误不同。我做错了什么...？？

app.component.ts：

import { Component, OnInit, ElementRef, ViewChild, Output, Input, EventEmitter } from '@angular/core';
import { CompositeFilterDescriptor, FilterDescriptor, State, toODataString, normalizeFilters } from '@progress/kendo-data-query';

declare var kendo: any;

@Component({
    selector: 'my-app',
    template: `
        <div #positionFilter></div>
    `
})
export class AppComponent implements OnInit {
    @ViewChild('positionFilter',{static: true}) positionFilter: ElementRef;
    public filterExpression: CompositeFilterDescriptor;
 public state: State = {
    skip: 0,
    take: 5,
    // Initial filter descriptor
    filter: null
  };

   ngOnInit() {
         this.loadFilter(this.positionFilter.nativeElement,  this.filterExpression);

   }

   public loadFilter(filterContainer,  expressionVal) {
    kendo.jQuery(filterContainer).kendoFilter({
      dataSource: [],
      //applyButton: false,
      expressionPreview: true,
      expression: expressionVal,
      change: this.onChangeFieldDropDownEvent.bind(this),
      fields: [
          { name: "ProductName",type: "string", label: "String" },
          { name: "CategoryID", type: "number", label: "Number"},
          { name: "UnitPrice", type: "boolean", label: "boolean"},
          { name: "UnitsInStock", type: "date", label: "Date" }
      ]
    });
  }



  onChangeFieldDropDownEvent(e) {
    console.log('Filter Expression--', e.expression);
    this.addSearch();
    this.filterExpression = e.expression;//.filters;
    this.updateState(this.filterExpression);
    let serializedFilterValue = this.serializeFilter(this.state);
    console.log('serializedFilterValue----', serializedFilterValue)

  }

  public updateState(filter) {
    this.state.filter = filter;
  }
  private serializeFilter(state: State): string {
    return toODataString(state);
  }

   public addSearch() {
    let container = this.positionFilter.nativeElement;
    kendo.jQuery(container).find(".k-filter-field select.k-filter-dropdown").each(function (i, x) {
      kendo.jQuery(x).data("kendoDropDownList").setOptions({ filter: "contains" });
    });
  }
}

【问题讨论】：

toODataQuery 不支持分组，OData v4 的剑道网格也不支持；我之前已经咨询过 Telerik 支持。

标签： kendo-ui odata kendo-ui-angular2

【解决方案1】：

我已经向剑道团队提出了这个问题。

这是他们的建议：

由于 toODataString 无法序列化空过滤器对象，因此出现此问题。一种可能的解决方案是在序列化参数之前删除所有空过滤器。例如

  private serializeFilter(state: State): string {
    removeEmptyFilters(state.filter)
    return toODataString(state);
  }

  function removeEmptyFilters(expression){
    var that = this;
            if (expression.filters) {
            expression.filters =  kendo.jQuery.grep(expression.filters, function(filter) {
                removeEmptyFilters(filter);
                if (filter.filters) {
                    return filter.filters.length;
                } else {
                    return filter.value;
                }
            });
        }
  }

【讨论】：