更少的try-catch語句？

Question

我有點沮喪，試圖找出最好的路線是用try-catch語句處理C＃中的異常。我想擁有代碼，所以如果試圖打開一個註冊表項引發異常，那麼它會移動到下一個註冊表項。我能想到的唯一方法就是通過將每個函數調用封裝在try-catch語句中，但對我來說，這似乎有很長的路要走。

• 有沒有其他方法可以做到這一點？
• 你可以擁有單個try-catch語句中的所有代碼，並且當發生異常時，是否將它移動到下一行代碼中（如step over）？
• 我知道這可能是一個否，但如果變量設置在參數中，可以使用ScanSubKey函數檢查異常嗎？

沒有的try-catch語句

ScanSubKey(Registry.ClassesRoot); 
ScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE")); 
ScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE")); 
if (Is64BitOS) 
{ 
    ScanSubKey(Registry.ClassesRoot.OpenSubKey("Wow6432Node")); 
    ScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE\\Wow6432Node")); 
    ScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE\\Wow6432Node")); 
} 

例

try { 
    ScanSubKey(Registry.ClassesRoot); 
} 
catch (Exception ex) { 
    Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
} 
try { 
    ScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE")); 
} 
catch (Exception ex) { 
    Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
} 
try { 
    ScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE")); 
} 
catch (Exception ex) { 
    Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
} 

if (Is64BitOS) 
{ 
    try { 
     ScanSubKey(Registry.ClassesRoot.OpenSubKey("Wow6432Node")); 
    } 
    catch (Exception ex) { 
     Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
    } 
    try { 
     ScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE\\Wow6432Node")); 
    } 
    catch (Exception ex) { 
     Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
    } 
    try { 
     ScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE\\Wow6432Node")); 
    } 
    catch (Exception ex) { 
     Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
    } 
} 

Answer 1

我把這叫做 「執行人」：

public static void Execute(Action action) 
    { 
     try 
     { 
      action(); 
     } 
     catch (Exception ex) 
     { 
     } 
    } 

，然後使用它：

Execute(() => ScanSubKey(Registry.ClassesRoot)); 

Answer 2

也許這將是一個更好的方法：

public bool TryOpenRegKey(RegistryKey regKey, string subKey = default(string)) 
{ 
    try 
    { 
    if (string.IsNullOrWhiteSpace(subKey)) 
     ScanSubKey(regKey); 
    else 
     ScanSubKey(regKey.OpenSubKey(subKey)); 

    return true; 
    } 
    catch(Exception ex) 
    { 
    Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
    return false; 
    } 
} 

然後：

TryOpenRegKey(Registry.ClassesRoot); 
TryOpenRegKey(Registry.LocalMachine, "SOFTWARE"); 
TryOpenRegKey(Registry.CurrentUser, "SOFTWARE"); 

if (Is64BitOS) 
{ 
    TryOpenRegKey(Registry.ClassesRoot, "Wow6432Node"); 
    TryOpenRegKey(Registry.LocalMachine, "SOFTWARE\\Wow6432Node"); 
    TryOpenRegKey(Registry.CurrentUser, "SOFTWARE\\Wow6432Node"); 
} 

Answer 3

你有沒有考慮把一個try/catch的ScanSubKey函數內本身並在發生錯誤時返回？

Answer 4

創建一個新方法TryScanSubKey。那麼你的代碼看起來又幹淨：

TryScanSubKey(Registry.ClassesRoot); 
TryScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE")); 
TryScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE")); 
if (Is64BitOS) 
{ 
    TryScanSubKey(Registry.ClassesRoot.OpenSubKey("Wow6432Node")); 
    TryScanSubKey(Registry.LocalMachine.OpenSubKey("SOFTWARE\\Wow6432Node")); 
    TryScanSubKey(Registry.CurrentUser.OpenSubKey("SOFTWARE\\Wow6432Node")); 
} 

的TryScanSubKey的實施應該是顯而易見的，但是，爲了完整起見，在這裏它是：

void TryScanSubKey(RegistryKey key) 
{ 
    try 
    { 
     ScanSubKey(key); 
    } 
    catch (Exception ex) 
    { 
     Debug.WriteLine("The following error occurred opening a registry key: " + ex.Message); 
    } 
} 

需要注意的是，一般，吞嚥的誤差不好的做法，併吞咽全部錯誤仍然更糟糕。所以請考慮（至少）用更具體的東西代替catch (Exception ex)，例如catch (TheSpecificExceptionThrownByScanSubKey ex)。