是否有一种方法可以通过多个case语句而不声明case值:重复?

我知道这很管用:

switch (value)
{
   case 1:
   case 2:
   case 3:
      // Do some stuff
      break;
   case 4:
   case 5:
   case 6:
      // Do some different stuff
      break;
   default:
       // Default stuff
      break;
}

但我想这样做:

switch (value)
{
   case 1,2,3:
      // Do something
      break;
   case 4,5,6:
      // Do something
      break;
   default:
      // Do the Default
      break;
}

这是我从另一种语言中想到的语法,还是我遗漏了什么?


当前回答

我们还可以使用这种方法在switch语句中实现Multiple case…使用这种方法,您可以使用任意多的条件。

    int i = 209;
    int a = 0;
    switch (a = (i>=1 && i<=100) ? 1 : a){    
    case 1:
        System.out.println ("The Number is Between 1 to 100 ==> " + i);
        break;
    default:
        switch (a = (i>100 && i<=200) ? 2 : a) {
            case 2:
                System.out.println("This Number is Between 101 to 200 ==> " + i);
                break;
        
            default:
                switch (a = (i>200 && i<=300) ? 3 : a) {
                    case 3:
                        System.out.println("This Number is Between 201 to 300 ==> " + i);
                        break;
                
                    default:
                        // You can make as many conditions as you want;
                        break;
                }
        }
        
    }

其他回答

此语法来自Visual Basic Select…Case语句:

Dim number As Integer = 8
Select Case number
    Case 1 To 5
        Debug.WriteLine("Between 1 and 5, inclusive")
        ' The following is the only Case clause that evaluates to True.
    Case 6, 7, 8
        Debug.WriteLine("Between 6 and 8, inclusive")
    Case Is < 1
        Debug.WriteLine("Equal to 9 or 10")
    Case Else
        Debug.WriteLine("Not between 1 and 10, inclusive")
End Select

在c#中不能使用此语法。相反,您必须使用第一个示例中的语法。

我们还可以使用这种方法在switch语句中实现Multiple case…使用这种方法,您可以使用任意多的条件。

    int i = 209;
    int a = 0;
    switch (a = (i>=1 && i<=100) ? 1 : a){    
    case 1:
        System.out.println ("The Number is Between 1 to 100 ==> " + i);
        break;
    default:
        switch (a = (i>100 && i<=200) ? 2 : a) {
            case 2:
                System.out.println("This Number is Between 101 to 200 ==> " + i);
                break;
        
            default:
                switch (a = (i>200 && i<=300) ? 3 : a) {
                    case 3:
                        System.out.println("This Number is Between 201 to 300 ==> " + i);
                        break;
                
                    default:
                        // You can make as many conditions as you want;
                        break;
                }
        }
        
    }

你可以省略换行符,它会给你:

case 1: case 2: case 3:
   break;

但我认为那是不好的风格。

下面的代码将无法工作:

case 1 | 3 | 5:
// Not working do something

做到这一点的唯一方法是:

case 1: case 2: case 3:
// Do something
break;

您正在寻找的代码在Visual Basic中工作,您可以轻松地将范围…在switch语句的none选项中,或者如果else blocks方便,我建议,在非常极端的情况下,用Visual Basic生成.dll,然后导入回c#项目中。

注意:在Visual Basic中等效的开关是“选择大小写”。

你也可以有完全不同的情况

            bool isTrue = true;

            switch (isTrue)
            {
                case bool ifTrue when (ex.Message.Contains("not found")):
                case bool ifTrue when (thing.number = 123):
                case bool ifTrue when (thing.othernumber != 456):
                    response.respCode = 5010;
                    break;
                case bool ifTrue when (otherthing.text = "something else"):
                    response.respCode = 5020;
                    break;
                default:
                    response.respCode = 5000;
                    break;
            }