Angular中数据循环ngFor、条件判断ngIf、ngSwitch、执行事件(click)、表单事件(keyup)、ngClass、ngStyle的使用

柔情只为你懂 2023-10-07 13:32 12阅读 0赞

## 场景 ##

Angular介绍、安装Angular Cli、创建Angular项目入门教程：

[https://blog.csdn.net/BADAO\_LIUMANG\_QIZHI/article/details/105570017][https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_105570017]

Angular新建组件以及组件之间的调用：

[https://blog.csdn.net/BADAO\_LIUMANG\_QIZHI/article/details/105694997][https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_105694997]

通过以上搭建起Angular项目，怎样进行简单的逻辑判断等。

注：

博客：  
[https://blog.csdn.net/badao\_liumang\_qizhi][https_blog.csdn.net_badao_liumang_qizhi]  
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## 实现 ##

### 数据循环ngFor ###

首先声明一个数组

public list1 = ["霸道","流氓","气质"]

然后在html中

效果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70][]

还可以使用Index获取其索引

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 1][]

### 条件判断ngIf ###

利用上面的list1的长度作为判断条件

<p *ngIf="list1.length >3">如果list1长度>3则显示</p>
    <p *ngIf="list1.length == 3">如果list1长度==3则显示</p>
    <p *ngIf="list1.length < 3">如果list1长度<3则显示</p>

### ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 2][] ###

### 选择语句ngSwitch ###

首先声明状态属性

public state = "2"

然后在html中

switch的结果是：<br>
    <ul [ngSwitch]="state">
        <li *ngSwitchCase="1">霸道</li>
        <li *ngSwitchCase="2">流氓</li>
        <li *ngSwitchCase="3">气质</li>
        <li *ngSwitchDefault>气质</li>
    </ul>

效果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 3][]

### 执行事件click ###

首先在html中添加一个Button并绑定其点击事件为getData()方法

<button class = "button" (click) = "getData()">点击获取数据</button>

然后在ts中

public title = "霸道流氓气质"
    
      getData(){
        alert(this.title);
      }

效果

![20200424133231687.gif][]

### 表单事件 ###

在html中添加一个input并绑定它的keyup事件，并且通过$event获取参数

然后在ts中

keyup(e)
      {
        console.log(e);
      }

运行并在输入框中随便输入

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 4][]

### ngClass ###

给div绑定提前声明好的样式，首先打开scss文件，声明两个红绿样式

.red {
        color: red;
      }
    
    .blue {
        color: blue;
      }

然后打开ts文件声明一个flag

public flag = false;

最后在html中

<div [ngClass] ="{'red':flag,'blue':!flag}">ngClass的Div</div>

然后运行看效果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 5][]

### ngStyle ###

如果不想提前声明好样式而是直接在代码中设置样式，可以这样

<div [ngStyle]="{'background-color':'red'}">霸道流氓气质</div>

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0JBREFPX0xJVU1BTkdfUUlaSEk_size_16_color_FFFFFF_t_70 6][]

[https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_105570017]: https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/105570017
[https_blog.csdn.net_BADAO_LIUMANG_QIZHI_article_details_105694997]: https://blog.csdn.net/BADAO_LIUMANG_QIZHI/article/details/105694997
[https_blog.csdn.net_badao_liumang_qizhi]: https://blog.csdn.net/badao_liumang_qizhi
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[20200424133231687.gif]: https://img-blog.csdnimg.cn/20200424133231687.gif
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