C# Switch If 条件来扩展 switch case

Question

我有一些数据需要转换，为此我需要一个超过 50 个案例的切换条件，我需要 3 次相同的案例，但在第三次我需要 50 个案例和一些更多，我不想写两次相同的代码。也许有可能做这样的事情。

switch (example)
{
    case "1":
        //do something
    case "2":
        //do something
    case "50":
        //do something
    //now maybe something like this
    if (condition == true)
    {
        case "1":
            //do something else than above at case "1", and so on 
            //now its i little bit illogical, but i neet to do the first 50 cases and then
            //use the cases 1 to 50 again but with other actions 
    }
}

Answer 1

从 C# 7 开始，您可以组合 the case statement with when clause并使用它来稍微简化您的代码

switch (example)
{
    case "1":
        //do something
    case "2":
        //do something
    case "50":
        //do something
    //now maybe something like this
    case "51" when condition == true:
        //do something, and so on  
    default:
        break;   
}

Starting with C# 7.0, because case statements need not be mutually exclusive, you can add a when clause to specify an additional condition that must be satisfied for the case statement to evaluate to true. The when clause can be any expression that returns a Boolean value.