我有一个角度为 4 的表单，其中包含名字 + 姓氏和一个包含 2 个下拉列表（选择）的表单数组，用作级联下拉列表和一个删除按钮。表单的其余部分还包含一个发送按钮和一个添加选项按钮。我在这里添加了一个屏幕截图，以便您更好地理解。表单添加、删除按钮和发送按钮有效存在 1 个问题，级联下拉菜单仅在有 1 个级联下拉菜单时才有效，当我添加额外的级联时，从前几组级联选择第二个选择中选择值搞砸了。我在这里添加了图片以获得更好的解释
正如您在第二张和第三张图片中看到的那样，cascadingdropdown 正在工作当我在标准中更改选择时，我在第二张下拉列表中选择了正确的选项
在第 4 张图片第 5 张图片和第 6 张图片上，您可以看到添加选项按钮有效，但是当我在选项 2 第一个下拉列表中选择一个标准时，它与选项 1 2nd Dropwown 混淆了，现在它也包含来自第二个选项的下拉选项
这是我的html代码
<form [formGroup] = "profileForm">
<h1>Profile Form</h1>
<div>
<label for = "first-name-input">First Name</label>
<input type="text" id="first-name-input" formControlName ="firstNameInput">
</div>
<div>
<label for = "last-name-input">Last Name</label>
<input type="text" id="last-name-input" formControlName ="lastNameInput">
</div>
<div formArrayName="optionGroups">
<div *ngFor="let optionGroup of profileForm.controls['optionGroups'].controls; let i=index "[formGroup]="optionGroup">
<h4>Option {{ i + 1 }} </h4>
<div>
<label for = "select-input">Criteria</label>
<select id="select-input" (change)="onSelectSelect($event.target.value, i)" formControlName ="selectInput">
<option value="0" disabled selected>Select a Criteria</option>
<option *ngFor="let select of selects" [value]= "select.name">{{select.id}}</option>
</select>
<label for = "where-input">Option</label>
<select id="where-input" formControlName ="whereInput">
<option value="0" disabled selected>Select a Option</option>
<option *ngFor="let where of wheres" value= {{where.name}}>{{where.id}}</option>
</select>
<button type ="button" (click)="removeOptionGroup(i)">X</button>
</div>
</div>
</div>
<button type ="button" (click)="addOptionGroup()">Add Options</button>
<div>
<button type ="button" (click)="saveProfileForm()">Send </button>
</div>
</form>这是我的组件文件
export class PowComponent {
selects: Select[];
wheres: Where[];
public profileForm : FormGroup;
public addOptionGroup(){
const fa = this.profileForm.controls["optionGroups"] as FormArray;
fa.push(this.newOptionGroup());
}
public removeOptionGroup(index: number){
const fa = this.profileForm.controls["optionGroups"] as FormArray;
fa.removeAt(index);
}
public saveProfileForm(){
console.log(this.profileForm.value);
}
constructor(public router: Router, public dropdownqueryservice: DropDownQueryService , private fb : FormBuilder) {
this.profileForm = this.fb.group({
firstNameInput : [ "" ],
lastNameInput : [ "" ],
optionGroups : this.fb.array([
this.fb.group({
selectInput : [ "" ],
whereInput : [ "" ],
}),
]),
});
this.selects = this.dropdownqueryservice.getSelect();
this.wheres=[];
}
onSelectSelect(selectid, i) {
this.wheres = this.dropdownqueryservice.getWhere().filter((item)=> item.selectid == selectid);
}
private newOptionGroup() {
return new FormGroup({
selectInput: new FormControl(""),
whereInput: new FormControl(""),
});
}
}