问题

我有一个不同AppTypes的枚举。

public enum AppType
{
    DefaultApps = 1,
    GlobalApps = 3,
    PrivateApps = 'L'
}

我将收到一个形如"1"、"3"或"L"的字符串，并希望在switch语句中使用它。

我尝试像下面这样做，但不起作用。我漏掉了什么吗？

switch (appTypeString)
{
  case $"{(char)AppType.DefaultApps}":
    Console.WriteLine("Default Catalog Apps");
    break;
  case nameof(AppType.GlobalApps):
    Console.WriteLine("Global Catalog Apps");
    break;
  case nameof(AppType.PrivateApps):
    Console.WriteLine("Private Catalog Apps");
    break;
  default:
    Console.WriteLine("Unknown App Type");
    break;
}

public enum AppType
{
    DefaultApps = 1,
    GlobalApps = 3,
    PrivateApps = 'L'
}

switch (appTypeString)
{
  case $"{(char)AppType.DefaultApps}:": // also tried nameof(AppType.GlobalApps)
    Console.WriteLine("Default Catalog Apps");
    break;
  case nameof(AppType.GlobalApps):
    Console.WriteLine("Global Catalog Apps");
    break;
  case nameof(AppType.PrivateApps):
    Console.WriteLine("Private Catalog Apps");
    break;
  default:
    Console.WriteLine("Unknown App Type");
    break;
}

答案1

得分: 2

以下是翻译好的代码部分：

你可以这样做：

AppType test = AppType.DefaultApps;
switch (test)
{
case AppType.DefaultApps:
Console.WriteLine("默认目录应用");
break;
case AppType.GlobalApps:
Console.WriteLine("全局目录应用");
break;
case AppType.PrivateApps:
Console.WriteLine("私有目录应用");
break;
default:
Console.WriteLine("未知应用类型");
break;
}

在你的情况下，你的输入是一个字符串，我会这样做：

```csharp
string val = "L";
AppType test;
bool flag = Enum.TryParse(val, out test);
// 由于AppType.PrivateApps的类型是char，它将无法通过Enum.TryParse()，因此我们进行转换
if (!flag)
{
    if (val.Length == 1)
        test = (AppType)(val.ToCharArray().First());
}
switch (test)
{
    case AppType.DefaultApps: 
        Console.WriteLine("默认目录应用");
        break;
    case AppType.GlobalApps:
        Console.WriteLine("全局目录应用");
        break;
    case AppType.PrivateApps:
        Console.WriteLine("私有目录应用");
        break;
    default:
        Console.WriteLine("未知应用类型");
        break;
}

<details>
<summary>英文:</summary>

You can do like this:

AppType test = AppType.DefaultApps;
switch (test)
{
case AppType.DefaultApps:
Console.WriteLine("Default Catalog Apps");
break;
case AppType.GlobalApps:
Console.WriteLine("Global Catalog Apps");
break;
case AppType.PrivateApps:
Console.WriteLine("Private Catalog Apps");
break;
default:
Console.WriteLine("Unknown App Type");
break;
}

In your case you have a string as the Input, I would do like this:

string val = "L";
AppType test;
bool flag = Enum.TryParse(val, out test);
//Since AppType.PrivateApps is of type char it will fail the Enum.TryParse() so we make a conversion
if (!flag)
{
if(val.Length == 1)
test = (AppType)(val.ToCharArray().First());
}
switch (test)
{
case AppType.DefaultApps:
Console.WriteLine("Default Catalog Apps");
break;
case AppType.GlobalApps:
Console.WriteLine("Global Catalog Apps");
break;
case AppType.PrivateApps:
Console.WriteLine("Private Catalog Apps");
break;
default:
Console.WriteLine("Unknown App Type");
break;
}

</details>



# 答案2
**得分**: 0

你还可以使用新的 `switch` 表达式：
```cs
var toPrint = appTypeString switch
  {
      AppType.DefaultApps => "默认目录应用",
      AppType.GlobalApps => "全局目录应用",
      AppType.PrivateApps => "私有目录应用",
      _ => "未知应用类型",
  };

Console.WriteLine(toPrint);

var toPrint = appTypeString switch
  {
      AppType.DefaultApps => "Default Catalog Apps",
      AppType.GlobalApps => "Global Catalog Apps",
      AppType.PrivateApps => "Private Catalog Apps",
      _ => "Unknown App Type",
  };

Console.WriteLine(toPrint);