共享衝突爲我的日誌管理

Question

我使用這個代碼在5月C＃MonoTouch的應用程序中保存的日誌：

public static void writeExeption(string message){ 
     string path= StorageClass .LogsPath ; 
     string filepath= Path.Combine (path ,"Log.txt"); 
     if(!File.Exists (filepath)){ 
      using (StreamWriter sw = File.CreateText(filepath)) 
      { 
       sw.WriteLine ("--------------------------------------------------------------------------" + 
           "--------------------"); 
       sw.WriteLine("blahblah..."); 
       sw.WriteLine ("--------------------------------------------------------------------------" + 
           "--------------------"); 
      } 
     } 
     using (StreamWriter w = File.AppendText(filepath)) 
     { 
      Log(message , w); 
     } 
    } 

    public static void Log(string logMessage, TextWriter w) 
    { 
     w.Write("\r\nLog Entry : "); 
     w.WriteLine("{0} {1}", DateTime.Now.ToLongTimeString(), 
        DateTime.Now.ToLongDateString()); 
     w.WriteLine(" :"); 
     w.WriteLine(" :{0}", logMessage); 
     w.WriteLine ("--------------------------------------------------------------------------" + 
         "--------------------"); 
    } 

但在應用我得到這個錯誤：

Sharing violation on path 'File Path' 

Answer 1

嘗試添加以包含將數據附加到lock語句中的StreamWriter。 首先，添加一個目標是指：

static object _locker = new object(); 

然後，通過鎖定最後using語句修改writeExeption方法：

lock (_locker) 
{ 
    using (StreamWriter w = File.AppendText(filepath)) 
    { 
     Log(message, w); 
    } 
} 

如果這仍然不起作用，這意味着一些其他的應用程序使用您的文件。如果它工作，這意味着你正在登錄多個線程。

Answer 2

好像您正在兩個或更多位置訪問一個文件（可能位於不同的線程中）。

使用這些方法來讀/寫在多線程應用程序文件，以避免這樣的錯誤：

/// <summary> 
    /// Writes the file exclusively. No one could do anything with file while it writing 
    /// </summary> 
    /// <param name="path">Path.</param> 
    /// <param name="data">Data.</param> 
    public static void WaitFileAndWrite(string path, byte[] data) 
    { 
     while (true) { 
      Stream fileStream = null; 

      try { 
       // FileShare.None is important: exclusive access during writing 
       fileStream = File.Open(path, FileMode.Create, FileAccess.Write, FileShare.None); 
       fileStream.Write(data, 0, data.Length); 

       break; 
      } catch (IOException ex) { 
       Console.WriteLine (ex); 
       Thread.Sleep(10); 
      } finally { 
       if (fileStream != null) { 
        fileStream.Close(); 
       } 
      } 
     } 
    } 

    /// <summary> 
    /// Waits the file and read. 
    /// </summary> 
    /// <returns>The file and read.</returns> 
    /// <param name="fileName">File name.</param> 
    public static byte [] WaitFileAndRead(string fileName) 
    { 
     byte[] result = null; 

     if (File.Exists(fileName)) { 
      while (true) { 
       Stream fileStream = null; 

       try { 
        fileStream = File.OpenRead(fileName); 
        var length = fileStream.Length; 
        result = new byte[length]; 
        fileStream.Read(result, 0, Convert.ToInt32(length)); 
        break; 
       } catch (IOException ex) { 
        Console.WriteLine (ex); 
        Thread.Sleep(10); 
       } finally { 
        if (fileStream != null) { 
         fileStream.Close(); 
        } 
       } 
      } 
     } 

     return result; 
    } 
} 

然而，你應該是準確的。如果有人打開文件進行讀/寫操作並且不關閉它，這些方法將嘗試無限打開。