2012-04-17 66 views
0

我想用.NET创建图像。以下是我正在使用的代码。这在大多数情况下都能正常工作,但有时候我猜想流被切断了,并且我有一个损坏的文件。我通过它的URL获取图片。.NET创建损坏的文件

我真的很想找人来纠正我的代码,或者让我知道我还能做些什么。

感谢

// Function will return the number of bytes processed 
     // to the caller. Initialize to 0 here. 
     int bytesProcessed = 0; 

     // Assign values to these objects here so that they can 
     // be referenced in the finally block 
     Stream remoteStream = null; 
     Stream localStream = null; 
     WebResponse response = null; 

     // Use a try/catch/finally block as both the WebRequest and Stream 
     // classes throw exceptions upon error 
     try 
     { 
      // Create a request for the specified remote file name 
      WebRequest request = WebRequest.Create(remoteFilename); 
      if (request != null) 
      { 
       // Send the request to the server and retrieve the 
       // WebResponse object 
       response = request.GetResponse(); 
       if (response != null) 
       { 
        // Once the WebResponse object has been retrieved, 
        // get the stream object associated with the response's data 
        remoteStream = response.GetResponseStream(); 

        // Create the local file 
        localStream = File.Create(localFilename); 

        // Allocate a 1k buffer 
        byte[] buffer = new byte[1024]; 
        int bytesRead; 

        // Simple do/while loop to read from stream until 
        // no bytes are returned 
        do 
        { 
         // Read data (up to 1k) from the stream 
         bytesRead = remoteStream.Read(buffer, 0, buffer.Length); 

         // Write the data to the local file 
         localStream.Write(buffer, 0, bytesRead); 

         // Increment total bytes processed 
         bytesProcessed += bytesRead; 
        } while (bytesRead > 0); 
       } 
      } 
     } 
     catch (Exception e) 
     { 
      throw e; 
     } 
     finally 
     { 
      // Close the response and streams objects here 
      // to make sure they're closed even if an exception 
      // is thrown at some point 
      if (response != null) response.Close(); 
      if (remoteStream != null) remoteStream.Close(); 
      if (localStream != null) localStream.Close(); 
     } 

,我发现了以下错误:

Main Exception 
MESSAGE: Parameter is not valid. 
SOURCE: System.Drawing 
TARGETSITE: System.Drawing.Image FromStream(System.IO.Stream, Boolean, Boolean) 
STACKTRACE: at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData) 
      at Sitecore.Resources.Media.ImageMedia.GetImage() at Sitecore.Resources.Media.ImageMedia.UpdateMetaData(MediaStream mediaStream) 
      at Sitecore.Resources.Media.JpegMedia.UpdateMetaData(MediaStream mediaStream) at Sitecore.Resources.Media.MediaCreator.AttachStreamToMediaItem(Stream stream, String itemPath, String fileName, MediaCreatorOptions options) 
      at Sitecore.Resources.Media.MediaCreator.CreateFromStream(Stream stream, String filePath, MediaCreatorOptions options) 
      at Sitecore.Resources.Media.MediaCreator.CreateFromFile(String filePath, MediaCreatorOptions options) 
+1

是否有任何异常?他们说什么? – PaulG 2012-04-17 17:15:06

+0

为什么你只捕捉一个异常,然后丢掉堆栈跟踪?为什么不使用'using'语句? – 2012-04-17 17:16:11

+1

有时候,一个中断的TCP连接不会给出任何错误,但行为就像流达到了末尾一样。当我在C#中编写下载程序时,我下载到一个临时文件,并且只有在验证预期的大小(来自http标头)与下载的大小匹配后才将其移至目标文件名。 – CodesInChaos 2012-04-17 17:29:25

回答

1

的问题是与该文件由Windows被锁定。基本上,有两台服务器。将文件保存在应该已经存在的另一台服务器上,并且一切正常。