错误时更改材料输入的颜色

Question

当 md-input 脏且无效时，我想将其更改为红色（与 Image 中的 Country Dropdown 相同）。我浏览了很多文章，但没有发现任何帮助..

Answer 1

错误颜色设置为主题中的警告颜色。

https://material.angular.io/guide/theming

@import '~@angular/material/theming';
// Plus imports for other components in your app.

// Include the common styles for Angular Material. We include this here so that you only
// have to load a single css file for Angular Material in your app.
// Be sure that you only ever include this mixin once!
@include mat-core();

// Define the palettes for your theme using the Material Design palettes available in palette.scss
// (imported above). For each palette, you can optionally specify a default, lighter, and darker
// hue. Available color palettes: https://material.io/design/color/
$candy-app-primary: mat-palette($mat-indigo);
$candy-app-accent:  mat-palette($mat-pink, A200, A100, A400);

// The warn palette is optional (defaults to red).
$candy-app-warn:    mat-palette($mat-red);

// Create the theme object (a Sass map containing all of the palettes).
$candy-app-theme: mat-light-theme($candy-app-primary, $candy-app-accent, $candy-app-warn);

// Include theme styles for core and each component used in your app.
// Alternatively, you can import and @include the theme mixins for each component
// that you are using.
@include angular-material-theme($candy-app-theme);

Answer 2

可以通过 css 解决，但需要做好封装方面的准备，以避免像 ::ng-deep 这样的弃用变体。这里给出一个解决方案：

https://stackoverflow.com/a/46042645/2692283

以下是您案例的简短描述：

1. 在你的组件中设置encapsulation: ViewEncapsulation.None：

   import { ViewEncapsulation } from '@angular/core';
   
   @Component({
       ...
       encapsulation: ViewEncapsulation.None
   })
   

   这里给出更详细的解释：

   ::ng-deep going to be deprecated - Any alternatives?

2. 现在只需使用 css 将其变为红色即可：

   /* Sets the underline to red if dirty and invalid */
   .mat-form-field.ng-dirty.ng-invalid .mat-form-field-underline {
     background-color: red;
   }
   /* Sets the label to red if dirty and invalid */
   .mat-form-field.ng-dirty.ng-invalid .mat-form-field-label {
     color: red;
   }
   

它应该适用于 Angular 4 和 5。

Answer 3

你需要在css下面包含

 .mat-input-invalid .mat-input-placeholder {
    color: red;
}

.mat-input-invalid .mat-input-ripple {
    background-color: red;
}