我正在自定义角度材质的选择/自动完成功能，以允许嵌套下拉列表。
在这里，我试图同时搜索父级或子级值，但没有将其过滤掉。
此外，它应该像阿拉斯加（+2个）一样显示。
<mat-form-field appearance="fill">
<mat-label>Toppings</mat-label>
<!-- <input type="text" matInput placeholder="States Group" formControlName="stateGroup" required [matAutocomplete]="autoGroup">
<mat-autocomplete #autoGroup="matAutocomplete"> -->
<input type="text" matInput placeholder="Select Users" aria-label="Select Users" matInput [matAutocomplete]="auto" [formControl]="states">
<mat-autocomplete #auto="matAutocomplete">
<!-- <mat-select [formControl]="states" multiple> -->
<mat-select-trigger>
{{states.value ? states.value[0] : ''}}
<span *ngIf="states.value?.length > 1" class="example-additional-selection">
(+{{states.value.length - 1}} {{states.value?.length === 2 ? 'other' : 'others'}})
</span>
</mat-select-trigger>
<mat-optgroup *ngFor="let group of stateList">
<div>
<mat-checkbox [checked]="group.selected" (change)="toggleParent($event, group)"
(click)="$event.stopPropagation()">
{{group.letter}}
</mat-checkbox>
<button mat-button (click)="expandDocumentTypes(group)">
<mat-icon>keyboard_arrow_down</mat-icon>
</button>
</div>
<mat-option *ngFor="let name of group.names" [value]="name"
[ngClass]="isExpandCategory[group.letter] ? 'list-show' : 'list-hide'">
<mat-checkbox [checked]="group.checked" (change)="toggleSelection($event, name, group)"
(click)="$event.stopPropagation()">
{{name.type}}
</mat-checkbox>
</mat-option>
</mat-optgroup>
<!-- </mat-select> -->
</mat-autocomplete>
<!-- </mat-autocomplete> -->
</mat-form-field>
export class SelectCustomTriggerExample {
constructor(private _formBuilder: FormBuilder){}
// stateForm: FormGroup = this._formBuilder.group({
// stateGroup: '',
// });
// toppings = new FormControl();
isExpandCategory: boolean[] = [];
toppingList: string[] = ['Extra cheese', 'Mushroom', 'Onion', 'Pepperoni', 'Sausage', 'Tomato'];
stateRecord:any = [];
states = new FormControl();
expandDocumentTypes(group: any) {
console.log("expanding dropdown", group);
this.isExpandCategory[group.letter] = !this.isExpandCategory[group.letter];
// expand only selected parent dropdown category with that childs
}
toggleSelection(event:any, name: any, group: any) {
debugger;
console.log("toggleSelection", name, event.checked, group);
if(event.checked) {
console.log("stastateRecordtelist", this.stateRecord);
this.stateRecord.push(name.type);
this.states.setValue(this.stateRecord);
console.log("toggleselection ", this.states.value);
}
else {
this.stateRecord = this.stateRecord.filter((x:any) => x!== name.type);
console.log("else toggleselection", name, group, this.states.value);
this.states.setValue(this.states.value.filter((x:any) => x!== name.type));
console.log("after filter ", this.states.value);
//this.states.setValue([]);
}
}
toggleParent(event: any, group: any) {
debugger;
group.checked = event.checked;
console.log("event", event.checked, "group", group, "states value", this.states.value);
let states = this.states.value;
states = states ? states : [];
if(event.checked) {
states.push(...group.names.filter((x: any) => !states.includes(x.type)).map((x: any) => x.type))
} else {
console.log("else", states);
group.names.forEach((x: any) => {
if(states.indexOf(x.type) > -1) {
states.splice(states.indexOf(x.type), 1)
}
});
}
this.states.setValue(states);
console.log("statesvalue", this.states.value);
if(!event.checked) {
this.states.setValue(this.states.value.filter((x:any) => !x.includes(group.names)))
//this.states.setValue([]);
}
console.log("final statesvalue", this.states.value);
this.stateRecord = this.states.value;
}
stateList = [
{
"letter":"A",
"checked":false,
"names":[
{
"id":1,
"type":"Alabama"
},
{
"id":2,
"type":"Alaska"
},
{
"id":3,
"type":"Arizona"
},
{
"id":4,
"type":"Arkansas"
}
]
},
{
"letter":"C",
"checked":false,
"names":[
{
"id":8,
"type":"California"
},
{
"id":9,
"type":"Colorado"
},
{
"id":10,
"type":"Connecticut"
}
]
},
{
"letter":"D",
"checked":false,
"names":[
{
"id":18,
"type":"Delaware"
},
{
"id":19,
"type":"Denwer"
}
]
}
];
}
参考：
https://stackblitz.com/edit/angular-evacck-qubgyy
https://stackblitz.com/angular/eboprqqnooy
有人可以帮忙吗？
答案 0 :(得分：2)
此任务非常复杂，需要更多说明，也许可以通过https://www.npmjs.com/package/mat-select-autocomplete之类的专用库来解决
但是我喜欢您逐步使用此自定义控件，希望拥有比您已经实现的更好的东西。
让我们尝试解决您在此问题中指出的两个问题：
角度材料使我们可以define custom filter。您可以在示例中使用类似的逻辑。只需创建一个Observable即可监听FormControl的更改：
this.stateGroupOptions$ = this.states.valueChanges.pipe(
startWith(EMPTY_STRING),
...
map(value => this._filterGroup(value))
);
...
private _filterGroup(value: any) {
if (!this.searching || !value.trim()) {
return this.stateList;
}
value = value.trim().toLowerCase();
return this.stateList
.map(group => ({
...group,
names: group.names.filter(item => item.type.toLowerCase().includes(value))
}))
.filter(
group => group.letter.toLowerCase().includes(value) || group.names.length > 0
);
}
然后在您的选项列表中使用它
<mat-optgroup *ngFor="let group of stateGroupOptions$ | async">
Alaska (+2 others)。同样，在这种情况下具有专用功能-
displayWith input property
@Input() displayWith: ((value: any) => string) | null将选项的控制值映射到触发器中的显示值的功能。
html
<mat-autocomplete ... [displayWith]="displayWith"
ts
displayWith(names: StateName[]) {
if (!names || !names.length) {
return "";
}
return (
names[0].type +
(names.length > 1
? ` (+${names.length - 1} ${names.length === 2 ? "other" : "others"})`
: "")
);
}
此自定义实现的主要技巧是使模型在不同类型的数据之间保持一致：string（当用户开始键入内容时），Array（当您单击复选框并手动更新控件时）和Object（从下拉菜单中选择选项时）。
注意： 您仍然可以对其进行优化，也许还有许多尚未发现的问题。