无法读取 null 的属性“模式”答案

【问题标题】：Can not read property 'pattern' of null无法读取 null 的属性“模式”
【发布时间】：2019-02-24 06:59:12
【问题描述】：

我写了两个输入框并添加了模式属性。但是当我在第一个框中输入一些东西时，它可以正常工作，但是当我输入第二个时，它会抛出很多错误！我不知道代码有什么问题，这是我的错误。

    ERROR TypeError: Cannot read property 'pattern' of null
    at Object.eval [as updateDirectives] (RegisterComponent.html:1)
    at Object.debugUpdateDirectives [as updateDirectives] (core.js?09c9:11062)
    at checkAndUpdateView (core.js?09c9:10459)
    at callViewAction (core.js?09c9:10700)
    at execEmbeddedViewsAction (core.js?09c9:10663)
    at checkAndUpdateView (core.js?09c9:10460)
    at callViewAction (core.js?09c9:10700)
    at execEmbeddedViewsAction (core.js?09c9:10663)
    at checkAndUpdateView (core.js?09c9:10460)
    at callViewAction (core.js?09c9:10700)

ERROR CONTEXT DebugContext_ {view: {…}, nodeIndex: 9, nodeDef: {…}, elDef: {…}, elView: {…}}

这是我的html代码：

<input type="password" class="form-control" id="password" name="password"
     #password="ngModel"  pattern="^[A-z0-9_]+$"
    placeholder="{{'global.form.newpassword.placeholder' | translate}}"
    [(ngModel)]="registerAccount.password" minlength=5 maxlength=30 required>

<input type="password" class="form-control" id="confirmPassword" name="confirmPassword" #confirmPasswordInput="ngModel" pattern="^[A-z0-9_]+$"
placeholder="{{'global.form.confirmpassword.placeholder' | translate}}"
[(ngModel)]="confirmPassword" minlength=5 maxlength=30 required>

【问题讨论】：

标签： javascript html angular input

【解决方案1】：

<input id="password" name="password" class="form-control" type="password" placeholder="{{'global.form.newpassword.placeholder' | translate}}" #password="ngModel" pattern="^[A-z0-9_]+$" [(ngModel)]="registerAccount.password" minlength=5 maxlength=30 required>

<input type="password" class="form-control" id="confirmPassword" name="confirmPassword" #confirmPasswordInput="ngModel" pattern="^[A-z0-9_]+$" placeholder="{{'global.form.confirmpassword.placeholder' | translate}}" [(ngModel)]="confirmPasswordTest" minlength=5 maxlength=30 required>

【讨论】：

谢谢，30分钟前我还喜欢这个bug，复制一段代码的时候忘记改参数名了。