角材料形式验证错误 [英] Angular Material forms validation errors

问题描述

我有一个物料表单，其中有一个输入框:

I have a material form in which I have an input box:

<md-form-field class="input-full-width">
    <input mdInput class="form-control emp-info-input" type="text" placeholder="Description" formControlName="periodDesc">
    <md-error *ngIf="periodDesc.errors.required">This field is required</md-error>
</md-form-field>

Formbuilder:

Formbuilder:

this.apprperiod = this.fb.group({
      'periodDesc' : new FormControl(this.periodDesc, [Validators.required,Validators.maxLength(50)])
    }, {validator: CustomValidator.validate});

加载时出现以下错误:

错误TypeError:无法读取未定义的属性'hasError'
at Object.TestComponent._co [作为updateDirectives](test.html:33)
at Object.debugUpdateDirectives [作为updateDirectives](core.es5.js:13075)
在checkAndUpdateView(core.es5.js:12255)
在callViewAction(core.es5.js:12620)
在execComponentViewsAction(core.es5.js:12552)
在checkAndUpdateView(core.es5.js:12261)
在callViewAction(core.es5.js:12620)
在execEmbeddedViewsAction(core.es5.js:12578)
在checkAndUpdateView(core.es5.js:12256)
在callViewAction(core.es5.js:12620)

ERROR TypeError: Cannot read property 'hasError' of undefined
at Object.TestComponent._co [as updateDirectives] (test.html:33)
at Object.debugUpdateDirectives [as updateDirectives] (core.es5.js:13075)
at checkAndUpdateView (core.es5.js:12255)
at callViewAction (core.es5.js:12620)
at execComponentViewsAction (core.es5.js:12552)
at checkAndUpdateView (core.es5.js:12261)
at callViewAction (core.es5.js:12620)
at execEmbeddedViewsAction (core.es5.js:12578)
at checkAndUpdateView (core.es5.js:12256)
at callViewAction (core.es5.js:12620)

推荐答案

因为您必须从这样的表单中获取控件:

Because you have to get the control from the form like this :

<md-error *ngIf="apprperiod.get('periodDesc').errors.required">This field is required</md-error>

或

<md-error *ngIf="apprperiod.hasError('required', ['periodDesc'])">This field is required</md-error>

这篇关于角材料形式验证错误的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！