Javascript Angular 2 Material Input 动态更改占位符
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Angular 2 Material Input change placeholder dynamically
提问by maidi
I want to change the text of the input placeholder dynamically. The console.log already gives the updated string but the interface doesn't update so there stays the old placeholder. How can I get the Interface to recognize the change?
我想动态更改输入占位符的文本。console.log 已经提供了更新的字符串，但界面没有更新，所以保留了旧的占位符。我怎样才能让界面识别变化？
document.getElementById(this.implicKey).setAttribute('placeholder', options[i].implication);
console.log(document.getElementById(this.implicKey).getAttribute('placeholder'));
回答by CharanRoot
you can change your input placeholder dynamically like this
您可以像这样动态更改输入占位符
<md-input-container class="demo-full-width">
<input mdInput [(ngModel)]="firstname" placeholder="{{somePlaceholder}}" name="firstname" required>
<md-error>This field is required</md-error>
</md-input-container>
component.ts
组件.ts
somePlaceholder : string = "new value";
now you can change somePlaceholder value any where in the class.
现在您可以在类中的任何位置更改 somePlaceholder 值。
回答by EQuadrado
We can do that using property binding.
我们可以使用属性绑定来做到这一点。
In the HTML, use square brackets:
在 HTML 中，使用方括号：
<input formControlName="events" type="text" [placeholder]="newPlaceHolder">
In your typescript file, define the property:
在您的打字稿文件中，定义属性：
newPlaceHolder: string = "original place holder";
Then, change the property value:
然后，更改属性值：
newPlaceHolder= "my new place holder";
