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
为此，您将使用goto语句。如:
switch(value){
case 1:
goto case 3;
case 2:
goto case 3;
case 3:
DoCase123();
//This would work too, but I'm not sure if it's slower
case 4:
goto case 5;
case 5:
goto case 6;
case 6:
goto case 7;
case 7:
DoCase4567();
}
其他回答
更漂亮的处理方式
if ([4, 5, 6, 7].indexOf(value) > -1)
//Do something
您可以为具有相同结果的多个值执行此操作
gcc实现了对C语言的扩展，以支持顺序范围:
switch (value)
{
case 1...3:
//Do Something
break;
case 4...6:
//Do Something
break;
default:
//Do the Default
break;
}
编辑:刚刚注意到这个问题上有c#标签，所以gcc的答案可能没有帮助。
使用新版本的c#我已经这样做了
public string GetValue(string name)
{
return name switch
{
var x when name is "test1" || name is "test2" => "finch",
"test2" => somevalue,
_ => name
};
}
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;
}
为此，您将使用goto语句。如:
switch(value){
case 1:
goto case 3;
case 2:
goto case 3;
case 3:
DoCase123();
//This would work too, but I'm not sure if it's slower
case 4:
goto case 5;
case 5:
goto case 6;
case 6:
goto case 7;
case 7:
DoCase4567();
}
