FileStream fileStream = new FileStream(zipfilepath, FileMode.OpenOrCreate, FileAccess.Read);
byte[] buffer = new byte[fileStream.Length];
fileStream.Read(buffer, 0, buffer.Length);
Stream stream = new MemoryStream(buffer);
stream.Seek(0, SeekOrigin.Begin);
fileStream.Close();
//释放流
fileStream.Dispose();
File.Delete(zipfilepath);