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