FileUpload.SaveAs() 提示 无法访问已关闭的文件。 System.ObjectDisposedException:

FileUpload FileUp = (FileUpload)Session["FileUploadPath"];
string path = ConfigurationManager.AppSettings["InputFilePath"];
if (!Directory.Exists(path))
{
Directory.CreateDirectory(path);
}
string filename = DateTime.Now.ToString("ddHHmmss") + "_" + FileUp.FileName;
string serverFile = path + filename;
FileUp.SaveAs(serverFile);

http://blog.csdn.net/encienqi/article/details/6002071