if (GetUploadFileContent.PostedFile.InputStream.Length < 1)
        
{
            Msg.Text = "请选择文件";
return;
        }
        string 
FileName = GetUploadFileContent.FileName;//上传文件文件名 
string FilePath = 
GetUploadFileContent.PostedFile.FileName;//上传文件完整路径+文件名
string fileExtName = 
FileName.Substring(FileName.LastIndexOf(".") + 1, 3);
        if (fileExtName 
== "txt" || fileExtName == "TXT" || fileExtName == "xml" || fileExtName == 
"XML")
        {
            int FileLen = 
GetUploadFileContent.PostedFile.ContentLength;//获取上传文件的大小
byte[] input = new 
byte[FileLen];
            System.IO.Stream UpLoadStream = 
GetUploadFileContent.PostedFile.InputStream;
            
UpLoadStream.Read(input, 0, FileLen);
            UpLoadStream.Position = 
0;
            System.IO.StreamReader sr = new 
System.IO.StreamReader(UpLoadStream, System.Text.Encoding.Default);
          
  Msg.Text = sr.ReadToEnd();
            if (Msg.Text != "")
            
{
 //此处的Msg.Text 就是文本中文件内容!
} 
            }
else
           
 {
                Msg.Text = "文件为空!";
return;
            }
        
    sr.Close();
            UpLoadStream.Close();
            UpLoadStream 
= null;
            sr = null;
        }
        else
        {
  
          Msg.Text = "请选择要求的类型的文件!";
return;
        }
asp.net 上传XML,txt 直接读取文件内容,布布扣,bubuko.com
原文:http://www.cnblogs.com/wang-123/p/3730794.html