如何在React组件中使用switch语句?

我有一个React组件，在组件的渲染方法中，我有这样的东西:

render() {
    return (
        <div>
            <div>
                // removed for brevity
            </div>

           { switch(...) {} }

            <div>
                // removed for brevity
            </div>
        </div>
    );
}

Now the point is that I have two div elements, one at the top and one at the bottom, that are fixed. In the middle I want to have a switch statement, and according to a value in my state I want to render a different component. So basically, I want the two div elements to be fixed always, and just in the middle to render a different component each time. I'm using this to implement a multi-step payment procedure). Though, as is the code currently it doesn't work, as it gives me an error saying that switch is unexpected. Any ideas how to achieve what I want?

当前回答

Lenkan的回答是一个很好的解决方案。

<div>
  {{ beep: <div>Beep</div>,
     boop: <div>Boop</div>
  }[greeting]}
</div>

如果需要一个默认值，那么您甚至可以这样做

<div>
  {{ beep: <div>Beep</div>,
     boop: <div>Boop</div>
  }[greeting] || <div>Hello world</div>}
</div>

或者，如果这对你来说不太好，那么你可以做一些

<div>
  { 
    rswitch(greeting, {
      beep: <div>Beep</div>,
      boop: <div>Boop</div>,
      default: <div>Hello world</div>
    }) 
  }
</div>

with

function rswitch (param, cases) {
  if (cases[param]) {
    return cases[param]
  } else {
    return cases.default
  }
}

2019-01-04 19:04:06

其他回答

这是另一种方法。

render() {
   return {this[`renderStep${this.state.step}`]()}

renderStep0() { return 'step 0' }
renderStep1() { return 'step 1' }

2019-08-21 18:07:48

下面是一个使用按钮在组件之间切换的完整工作示例

可以按如下方式设置构造函数

constructor(props)
{
    super(props);
    this.state={
        currentView: ''
    }
}

然后您就可以像下面这样渲染组件了

  render() 
{
    const switchView = () => {

    switch(this.state.currentView) 
    {

      case "settings":   return <h2>settings</h2>;
      case "dashboard":   return <h2>dashboard</h2>;

      default:      return <h2>dashboard</h2>
    }
  }

    return (

       <div>

            <button onClick={(e) => this.setState({currentView: "settings"})}>settings</button>
            <button onClick={(e) => this.setState({currentView: "dashboard"})}>dashboard</button>

            <div className="container">
                { switchView() }
            </div>


        </div>
    );
}

}

正如你所看到的，我正在使用一个按钮来切换状态。

2020-02-23 18:26:54

我知道我有点晚了，但我认为这个实现可能会有所帮助

您可以使用条件操作符来呈现组件

如果你有下面的switch语句

switch(value) {
    case CASE1:
        return <Case1Component/>

    case CASE2:
        return <Case2Component/>

    case CASE3:
        return <Case3Component/>

    default:
        return <DefaultComponent/>
}

你可以像这样把它转换成react组件

const cases = [CASE0, CASE1, CASE2]
// Reminds me of 'react-router-dom'
return (
    <div>
        {value === cases[0] && <Case0Component/>}
        {value === cases[1] && <Case1Component/>}
        {value === cases[2] && <Case2Component/>}
        {!cases.includes(value) && <DefaultComponent/>}
    </div>
)

2021-06-21 13:46:00

React组件中的Switch-Case语句可以如下使用:

<div  id="time-list">
{   
    (() => {
        switch (groupByFilterId) {
            case 0:/*Case 0 */
                return (
                    <div>Case 0</div>
                )
               break;
           case 1: /*Case 1 */
           return ( 
            <div>Case 1</div>
            )
            break;
           case 2:/*Case 2 */
           return ( 
            <div>Case 2</div>
            )
            break;
        }
     })()}

      
       
    
    </div>

2021-05-09 12:05:43

我将接受的答案转换为箭头功能组件解决方案，看到James提供了类似的答案，可以得到未定义的错误。这就是解决方案:

  const renderSwitch = (param) => {
    switch (param) {
      case "foo":
        return "bar";
      default:
        return "foo";
    }
  };

  return (
    <div>
      <div></div>

      {renderSwitch(param)}

      <div></div>
    </div>
  );

2021-03-16 05:40:58

如何在React组件中使用switch语句?

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