多个当前请求到文件系统文件夹处理文件C＃XML

Question

我有一个文件夹存在于其中有很多XML文件的文件系统上。比方说10,000。

我有多个（5）Windows服务每30秒检查一次该文件夹并同时处理文件。我试图编写服务进程代码足够聪明，以便它可以处理并发处理请求。

但是它有时会挂在一些文件上。

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

我在处理过程中看到上面记录的约1％的文件错误。我能做些什么来改进下面的代码来防止这种情况发生？

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

替换 “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