我在父组件中有 Angular react 形式,在子组件中有部分。
在子组件中,我有一个复选框 - 当它被选中时 - 更多字段打开,我希望它们都是必需的。
我正在使用 setValidators 但出现错误
ParentFormComponent.html:3 ERROR Error: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'ng-valid: true'. Current value: 'ng-valid: false'. at viewDebugError (core.js:7601) at expressionChangedAfterItHasBeenCheckedError (core.js:7589) at checkBindingNoChanges (core.js:7691) at checkNoChangesNodeInline (core.js:10560) at checkNoChangesNode (core.js:10541) at debugCheckNoChangesNode (core.js:11144) at debugCheckRenderNodeFn (core.js:11098) at Object.eval [as updateRenderer] (ParentFormComponent.html:3) at Object.debugUpdateRenderer [as updateRenderer] (core.js:11087) at checkNoChangesView (core.js:10442)
ParentFormComponent.html:3 ERROR CONTEXT DebugContext_ {view: Object, nodeIndex: 2, nodeDef: Object, elDef: Object, elView: Object}
这是ParentFormComponent.html:3行
<form [formGroup]="parentForm" (ngSubmit)="submitForm()">
这是我的代码:
<label class="container">DB
<input #db type="checkbox" name="db" (change)="checkValue(db.name, db.checked)">
<span class="checkmark"></span>
</label>
<div *ngIf="db.checked" formGroupName="_monitorDB">
<mat-form-field>
<input matInput placeholder="Server name" formControlName="ServerName">
</mat-form-field>
<mat-form-field>
<input matInput placeholder="DataBase name" formControlName="DbName">
</mat-form-field>
<mat-form-field>
<input matInput placeholder="table name" formControlName="DB_tableName">
</mat-form-field>
<mat-form-field>
<input matInput placeholder="port" formControlName="DbPort">
</mat-form-field>
<mat-form-field>
<input matInput placeholder="Query" formControlName="Query">
</mat-form-field>
<mat-form-field>
<input matInput placeholder="Permissions" formControlName="Premissions">
</mat-form-field>
</div>
在ts文件中:
checkValue(name:string, event: any){
if (event == true){
this.test.push(name);
if (name =="db"){
this.childForm.get('_monitorDB').get('ServerName').setValidators([Validators.required]);
this.childForm.get('_monitorDB').get('DbName').setValidators([Validators.required]);
this.childForm.get('_monitorDB').get('DB_tableName').setValidators([Validators.required]);
this.childForm.get('_monitorDB').get('DbPort').setValidators([Validators.required]);
this.childForm.get('_monitorDB').get('Query').setValidators([Validators.required]);
this.childForm.get('_monitorDB').get('Premissions').setValidators([Validators.required]);
}
}
else{
const index: number = this.test.indexOf(name);
if (index !== -1) {
this.test.splice(index, 1);
if (name =="db"){
this.childForm.get('_monitorDB').get('ServerName').clearValidators();
this.childForm.get('_monitorDB').get('ServerName').updateValueAndValidity();
this.childForm.get('_monitorDB').get('DbName').clearValidators();
this.childForm.get('_monitorDB').get('DbName').updateValueAndValidity();
this.childForm.get('_monitorDB').get('DB_tableName').clearValidators();
this.childForm.get('_monitorDB').get('DB_tableName').updateValueAndValidity();
this.childForm.get('_monitorDB').get('DbPort').clearValidators();
this.childForm.get('_monitorDB').get('DbPort').updateValueAndValidity();
this.childForm.get('_monitorDB').get('Query').clearValidators();
this.childForm.get('_monitorDB').get('Query').updateValueAndValidity();
this.childForm.get('_monitorDB').get('Premissions').clearValidators();
this.childForm.get('_monitorDB').get('Premissions').updateValueAndValidity();
}
}
}
this.checkboxArr.emit(this.test);
}
最佳答案
我遇到了同样的问题,我使用 AfterViewChecked
和 ChangeDetectorRef
修复了它:
import { AfterViewChecked, ChangeDetectorRef } from '@angular/core'
export class ClassName implements AfterViewChecked {
constructor(private readonly changeDetectorRef: ChangeDetectorRef) {}
ngAfterViewChecked(): void {
this.changeDetectorRef.detectChanges();
}
}
关于angular - 检查后表达式发生了变化。先前值 : 'ng-valid: true' . 当前值: 'ng-valid: false',我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/53901392/