代码示例如下：
//提供下载源地址（在服务器上的地址）
string srcPath = “C:\text.txt”;
FileInfo fileInfo = new FileInfo(srcPath);
//若该文件存在则弹出对话框让你选择保存地址（本地）
if (fileInfo.Exists)
{
Response.AddHeader(“Content-Disposition”, “attachment;filename=” + fileInfo.Name);
Response.WriteFile(srcPath);
Response.Flush();
Response.Close();
}
补充：不弹出对话框代码如下：
/**//**//** <summary>
/** 下载文件
/** </summary>
/** <param name=”filename”>文件物理地址</param>
protected void DownloadFile(string filename)
…{
string saveFileName = “test.xls”;
int intStart = filename.LastIndexOf(“\”)+1;
saveFileName = filename.Substring(intStart,filename.Length-intStart);
FileStream MyFileStream;
long FileSize;
MyFileStream = new FileStream(filename,FileMode.Open);
FileSize = MyFileStream.Length;
byte[] Buffer = new byte[(int)FileSize];
MyFileStream.Read(Buffer, 0, (int)FileSize);
MyFileStream.Close();
Response.AddHeader(“Content-Disposition”, “attachment;filename=”+saveFileName);
Response.ContentEncoding = System.Text.Encoding.GetEncoding(“GB2312”);
Response.ContentType = “application/vnd.ms-excel”;
Response.BinaryWrite(Buffer);
Response.Flush();
Response.Close();
Response.End();
}