c# net 简单 上传和下载文件代码

简单案例 拿来就可以用了

//FileName要下载的文件路径

public static void FileDownload(string FileName) 
{ 
String FullFileName = System.Web.HttpContext.Current.Server.MapPath(FileName); 
FileInfo DownloadFile = new FileInfo(FullFileName); 
System.Web.HttpContext.Current.Response.Clear(); 
System.Web.HttpContext.Current.Response.ClearHeaders(); 
System.Web.HttpContext.Current.Response.Buffer = false; 
System.Web.HttpContext.Current.Response.ContentType = "application/octet-stream"; 
System.Web.HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + System.Web.HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8)); 
System.Web.HttpContext.Current.Response.AppendHeader("Content-Length", DownloadFile.Length.ToString()); 
System.Web.HttpContext.Current.Response.WriteFile(DownloadFile.FullName); 
System.Web.HttpContext.Current.Response.Flush(); 
System.Web.HttpContext.Current.Response.End(); 
} 
下载,直接调用方法

try 
{ 
if (FileUpload1.PostedFile.FileName.Length == 0) 
{ 
Response.Write("<script>alert(\"上传路径不能为空！\");</script>"); 
return; 
} 
string filename = this.FileUpload1.PostedFile.FileName.Substring(this.FileUpload1.PostedFile.FileName.LastIndexOf("\\") + 1); 
string houzhui = FileUpload1.PostedFile.FileName.Substring(this.FileUpload1.PostedFile.FileName.LastIndexOf(".") + 1); 
if (houzhui == "gif" || houzhui == "jpg" || houzhui == "bmp") 
{ 
FileUpload1.PostedFile.SaveAs(Server.MapPath("image/" + filename)); 
Response.Write("<script>alert(\"上传文件成功！\");</script>"); 
} 
else 
{ 
Response.Write("<script>alert(\"上传文件必须是gif,jpg,bmp格式！\");</script>"); 
return; 
} 
} 
catch (Exception ex) 
{ 
Response.Write("<script>alert(\"" + ex.Message + "\");</script>"); 
}