IOException: 磁盘空间不足。

StackTrace:
   在 System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   在 System.IO.FileStream.EndWrite(IAsyncResult asyncResult)
   在 Microsoft.Win32.WinInetCache.WriteStream.EndWrite(IAsyncResult asyncResult)
   在 System.IO.FileStream.FlushWrite(Boolean calledFromFinalizer)
   在 System.IO.FileStream.Dispose(Boolean disposing)
   在 Microsoft.Win32.WinInetCache.WriteStream.Dispose(Boolean disposing)
   在 System.IO.Stream.Close()
   在 Microsoft.Win32.WinInetCache.WriteStream.CloseEx(CloseExState closeState)
   在 System.Net.Cache.ForwardingReadStream.Dispose(Boolean disposing, CloseExState closeState)
   在 System.IO.Stream.Close()
   在 System.Windows.Media.Imaging.BitmapDownload.ReadCallback(IAsyncResult result)
   在 System.Net.LazyAsyncResult.Complete(IntPtr userToken)
   在 System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
   在 System.Net.Cache.ForwardingReadStream.ReadComplete(IAsyncResult transportResult)
   在 System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   在 System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   在 System.Threading.ThreadPoolWorkQueue.Dispatch()