当我尝试关闭响应时抛出 C# HTTPWebResponse 异常

在包含行 response.Close();

try 
{ 
    response = (FtpWebResponse)request.GetResponse(); 
} 
catch (System.Net.WebException webEx) 
{ 
    FtpWebResponse ftpResponse = (FtpWebResponse)webEx.Response; 
 
    if (ftpResponse.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable) 
    { 
        return false; 
    } 
 
    throw; 
} 
finally 
{ 
    if (response != null) 
    { 
        response.Close(); 
    } 
} 

这是堆栈跟踪:

   at System.Net.FtpWebRequest.SyncRequestCallback(Object obj) 
   at System.Net.FtpWebRequest.RequestCallback(Object obj) 
   at System.Net.CommandStream.Dispose(Boolean disposing) 
   at System.IO.Stream.Close() 
   at System.IO.Stream.Dispose() 
   at System.Net.ConnectionPool.Destroy(PooledStream pooledStream) 
   at System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse) 
   at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage) 
   at System.Net.FtpWebRequest.SyncRequestCallback(Object obj) 
   at System.Net.FtpWebRequest.RequestCallback(Object obj) 
   at System.Net.CommandStream.Abort(Exception e) 
   at System.Net.CommandStream.CheckContinuePipeline() 
   at System.Net.FtpWebRequest.DataStreamClosed(CloseExState closeState) 
   at System.Net.FtpDataStream.System.Net.ICloseEx.CloseEx(CloseExState closeState) 
   at System.Net.FtpDataStream.Dispose(Boolean disposing) 
   at System.IO.Stream.Close() 
   at System.Net.FtpWebResponse.Close() 
   at FVC.RequestForStock.Application.RequestForStockDataImportProvider.VerifyDirectoryExist(String serverAddress, String userName, SecureString password) in C:\CoName.RFS.Application\RFSDataImportProvider.cs:line 122 

最后是调试检查器显示的内容

(如果看不清文字，请放大图片，例如在 firefox 中按住 ctrl 并向上滚动鼠标滚轮) 有人可以协助确定异常发生的原因以及如何防止异常发生。 编辑:使用 Microsoft.NET 框架的 v4.0

请您参考如下方法:

我还会检查流是否仍然可读。

       finally 
        { 
            if (response != null &&  
                 response.GetResponseStream()!=null &&  
                 response.GetResponseStream().CanRead) 
                { 
                    response.Close(); 
                } 
            }