C#保存上传来的图片示例代码

[HttpPost] 
public string UploadImage() 
{ 
//string ss = Request.Form["uploadFile"]; 
//return ss; 
HttpPostedFileBase uploadFile = Request.Files[0]; 
string fileName = uploadFile.FileName; 
int fileSize = uploadFile.ContentLength; 
string fileExt = Path.GetExtension(fileName).ToLower(); 
string message = ""; 
if (!(fileExt == ".png" || fileExt == ".gif" || fileExt == ".jpg" || fileExt == ".jpeg")) 
{ 
message = "图片类型只能为gif,png,jpg,jpeg"; 
return message; 
} 
else 
{ 
if (fileSize > (int)(500 * 1024)) 
{ 
message = "图片大小不能超过500KB"; 
return message; 
} 
else 
{ 
Random r = new Random(); 
string uploadFileName = DateTime.Now.ToString("yyyyMMddhhmmss") + r.Next(100000, 999999) + fileExt; 
try 
{ 
string directoryPath = Server.MapPath("~/UploadImages/"); 
if (!Directory.Exists(directoryPath))//不存在这个文件夹就创建这个文件夹 
{ 
Directory.CreateDirectory(Server.MapPath("~/UploadImages/")); 
} 
uploadFile.SaveAs(Server.MapPath("~/UploadImages/") + uploadFileName); 
message = uploadFileName; 
return message; 
} 
catch (Exception ex) 
{ 
message = ex.Message; 
return message; 
} 
} 
} 
}