多個當前請求到文件系統文件夾處理文件C＃XML

Question

我有一個文件夾存在於其中有很多XML文件的文件系統上。比方說10,000。

我有多個（5）Windows服務每30秒檢查一次該文件夾並同時處理文件。我試圖編寫服務進程代碼足夠聰明，以便它可以處理併發處理請求。

但是它有時會掛在一些文件上。

E[The process cannot access the file '...' because it is being used by another process.] 

我在處理過程中看到上面記錄的約1％的文件錯誤。我能做些什麼來改進下面的代碼來防止這種情況發生？

class Program 
{ 
    private static string _instanceGuid; 
    static string InstanceGuid 
    { 
     get 
     { 
      if(_instanceGuid == null) 
      { 
       _instanceGuid = Guid.NewGuid().ToString(); 
      } 
      return _instanceGuid; 
     } 
    } 

    static void Main(string[] args) 
    { 
     string[] sourceFiles = Directory.GetFiles("c\\temp\\source\\*.xml") 
             .OrderBy(d => new FileInfo(d).CreationTime).ToArray(); 

     foreach (string file in sourceFiles) 
     { 
      var newFileName = string.Empty; 

      try 
      { 
       // first we'll rename in this way try and 
       // i would think it should throw an exception and move on to the next file. an exception being thrown means that file should already be processing by another service. 

       newFileName = string.Format("{0}.{1}", file, InstanceGuid); 
       File.Move(file, newFileName); 

       var xml = string.Empty; 
       using (var s = new FileStream(newFileName, FileMode.Open, FileAccess.Read, FileShare.None)) 
       using (var tr = new StreamReader(s)) 
       { 
        xml = tr.ReadToEnd(); 
       } 

       // at this point we have a valid XML save to db 
      } 
      catch (FileNotFoundException ex) 
      { 
       // continue onto next source file 
      } 
      catch (Exception ex) 
      { 
       // log error 
      } 
     } 
    } 
} 

Answer 1

替換 「FileShare.None」 到 「FileShare.Read」 上以下行：

  using (var s = new FileStream(newFileName, FileMode.Open, FileAccess.Read, FileShare.None)) 

http://msdn.microsoft.com/en-us/library/system.io.fileshare%28v=vs.110%29.aspx