在C#中使用枚举在Switch Case中：

huangapple
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英文:

Use an Enum in a Switch Case C#

问题

我有一个不同AppTypes的枚举。

  1. public enum AppType
  2. {
  3.     DefaultApps = 1,
  4.     GlobalApps = 3,
  5.     PrivateApps = 'L'
  6. }

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？

  1. switch (appTypeString)
  2. {
  3.   case $"{(char)AppType.DefaultApps}":
  4.     Console.WriteLine("Default Catalog Apps");
  5.     break;
  6.   case nameof(AppType.GlobalApps):
  7.     Console.WriteLine("Global Catalog Apps");
  8.     break;
  9.   case nameof(AppType.PrivateApps):
  10.     Console.WriteLine("Private Catalog Apps");
  11.     break;
  12.   default:
  13.     Console.WriteLine("Unknown App Type");
  14.     break;
  15. }
英文:

I have an Enum of different AppTypes.

  1. public enum AppType
  2. {
  3.     DefaultApps = 1,
  4.     GlobalApps = 3,
  5.     PrivateApps = 'L'
  6. }

I will receive a string of form "1", "3" or "L" and want to use this in switch statement.
I am trying to do as below. but not working. am I missing anything.

  1. switch (appTypeString)
  2. {
  3.   case $"{(char)AppType.DefaultApps}:": // also tried nameof(AppType.GlobalApps)
  4.     Console.WriteLine("Default Catalog Apps");
  5.     break;
  6.   case nameof(AppType.GlobalApps):
  7.     Console.WriteLine("Global Catalog Apps");
  8.     break;
  9.   case nameof(AppType.PrivateApps):
  10.     Console.WriteLine("Private Catalog Apps");
  11.     break;
  12.   default:
  13.     Console.WriteLine("Unknown App Type");
  14.     break;
  15. }

答案1

得分: 2

以下是翻译好的代码部分：

  1. 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;
}

  2. 在你的情况下，你的输入是一个字符串，我会这样做：
  4. ```csharp
  5. string val = "L";
  6. AppType test;
  7. bool flag = Enum.TryParse(val, out test);
  8. // 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
  9. if (!flag)
  10. {
  11.     if (val.Length == 1)
  12.         test = (AppType)(val.ToCharArray().First());
  13. }
  14. switch (test)
  15. {
  16.     case AppType.DefaultApps: 
  17.         Console.WriteLine("默认目录应用");
  18.         break;
  19.     case AppType.GlobalApps:
  20.         Console.WriteLine("全局目录应用");
  21.         break;
  22.     case AppType.PrivateApps:
  23.         Console.WriteLine("私有目录应用");
  24.         break;
  25.     default:
  26.         Console.WriteLine("未知应用类型");
  27.         break;
  28. }
  2. <details>
  3. <summary>英文:</summary>
  5. 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;
}

  2. 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;
}

  2. </details>
  6. # 答案2
  7. **得分**: 0
  9. 你还可以使用新的 `switch` 表达式：
  10. ```cs
  11. var toPrint = appTypeString switch
  12.   {
  13.       AppType.DefaultApps => "默认目录应用",
  14.       AppType.GlobalApps => "全局目录应用",
  15.       AppType.PrivateApps => "私有目录应用",
  16.       _ => "未知应用类型",
  17.   };
  19. Console.WriteLine(toPrint);
英文:

You can also use the new switch expression:

  1. var toPrint = appTypeString switch
  2.   {
  3.       AppType.DefaultApps =&gt; &quot;Default Catalog Apps&quot;,
  4.       AppType.GlobalApps =&gt; &quot;Global Catalog Apps&quot;,
  5.       AppType.PrivateApps =&gt; &quot;Private Catalog Apps&quot;,
  6.       _ =&gt; &quot;Unknown App Type&quot;,
  7.   };
  9. Console.WriteLine(toPrint);

huangapple
  • 本文由 发表于 2023年6月12日 23:45:52
  • 转载请务必保留本文链接：https://go.coder-hub.com/76458277.html
  • c#
  • enums
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