C# 文件操作

using System.IO;

Directory.CreateDirectory(FilePath);

【使用WriteFile下载文件】

using System.Net

private string fileName = HttpContext.Current.Server.UrlEncode("规范.rar"); 
private string filePath = HttpContext.Current.Server.MapPath("规范.rar"); 

//使用WriteFile下载文件 
protected void btnDL2_Click(object sender, EventArgs e) 
{ 
　　FileInfo info = new FileInfo(filePath); 
　　long fileSize = info.Length; 
　　Response.Clear(); 
　　Response.ContentType = "application/octet-stream"; 
　　Response.AddHeader("Content-Disposition", "attachement;filename=" + fileName); 
　　//指定文件大小 
　　Response.AddHeader("Content-Length", fileSize.ToString()); 
　　Response.WriteFile(filePath, 0, fileSize); 
　　Response.Flush(); 
　　Response.Close(); 
}