不，这不是您的元数据定义中的错误。这是设计使然。非标量导航属性由 Breeze 管理。多选控件尝试获取值数组的所有权并将其替换为新数组。 Breeze 不允许这样做，因为这将是灾难性的并破坏您的实体。
多选控件有点麻烦。您需要在用户进行选择时利用控件触发的事件来更新导航属性，并从所选值手动创建关联实体，并在用户取消选择它们时将其删除。我没有 KendoUI 的示例，但是 FWIW，这里是 DevExpress TagBox 和以下实体模型的 Angular2 示例。
Model(Subject) 1n SubjectVehicleAssociation n1 LookupItem(Vehicle)
这涉及到一些工作。开箱即用的多选控件仅适用于基本数组。
<dx-tag-box [dataSource]="adapter.dataSource"
displayExpr="description"
[value]="adapter.value"
[searchEnabled]="true"
(onSelectionChanged)="adapter.selectionChanged($event)">
</dx-tag-box>
在组件中创建适配器实例：
let valueConverter: ITagBoxValueConverter<SubjectVehicleAssociation, { code: string, longValue: string }> = {
match: (item: SubjectVehicleAssociation, lookupItem: { code: string, longValue: string }) => item.abbreviation === lookupItem.code,
seed: (item: SubjectVehicleAssociation, lookupItem: { code: string, longValue: string }) => {
item.description = lookupItem.longValue;
item.abbreviation = lookupItem.code;
return item;
}
};
this.adapter = new TagBoxAdapter(SubjectVehicleAssociation,
() => Promise.resolve(this.vehicleAssociationsLookup),
this.modelSubjectVehicleRelation,
'associations',
valueConverter);
以及适配器实现：
import DataSource from 'devextreme/data/data_source';
import * as _ from 'lodash';
import { Entity, EntityState } from 'breeze-client';
export interface ITagBoxValueConverter<T extends Entity, W> {
match(value1: T, value2: W): boolean;
seed(target: T, source: W): T;
}
export class TagBoxAdapter<T extends Entity, W> {
dataSource: DataSource;
constructor(private itemType: { new (): T },
private data: (searchValue?: string, maxSearchResults?: number) => Promise<W[]>,
private model: any,
private valueExpr: string,
private valueConverter: ITagBoxValueConverter<T, W>,
private maxSearchResults: number = 20) {
this.initializeDataSource();
}
get value(): T[] {
return _.get<T[]>(this.model, this.valueExpr, []);
}
selectionChanged(e: { addedItems: T[], removedItems: T[] }) {
e.addedItems.forEach(item => {
if (item.entityAspect && item.entityAspect.entityState.isDeleted()) {
// Real entity, needs to be resurrected
item.entityAspect.rejectChanges();
} else {
// Placeholder entity, needs to be attached first
this.model.entityAspect.entityManager.attachEntity(item, EntityState.Added);
this.value.push(item);
}
})
e.removedItems.forEach(item => {
item.entityAspect.setDeleted();
})
};
private initializeDataSource() {
let sourceData = (searchValue: string, maxSearchResults: number) => {
return this.data(searchValue, maxSearchResults).then((results) => {
return results.map(dataItem => {
// Find existing association entity if exists
let item = _.find(this.value, item => this.valueConverter.match(item, dataItem));
if (item) return item;
// Not associated yet, return placeholder association entity
return this.valueConverter.seed(new this.itemType(), dataItem);
})
});
};
this.dataSource = new DataSource({
// The LoadOptions interface is defined wrong it's lacking the search properties
load: (loadOptions: any) => {
let searchValue = loadOptions.searchValue ? loadOptions.searchValue : "";
return sourceData(searchValue, this.maxSearchResults).then(data => data.filter(item => !_.intersection(this.value, [item]).length));
},
byKey: (key) => {
return sourceData(key, 1).then((data) => _.find(data, key));
}
});
}
}