图片上传后台实现方法

var request = this.Context.Request;

HttpPostedFile files = request.Files["idFile"];

string newname = null;

if (files.ContentLength > 0) {
            try  
            {      
                string url;  
                string urlsql;
               var jurl =  AppDomain.CurrentDomain.BaseDirectory;
               var fod = "UpImageFiles/";
                
                string fn = files.FileName.Substring(files.FileName.LastIndexOf("//") + 1);//获取文件名  
                int j = fn.LastIndexOf(".");
                string newexts = fn.Substring(j);
                string pname = IDCard;
                 newname = pname + newexts;
                string fp = "../UpImageFiles/";//服务器实际文件夹地址  
                string fpsql = "~/UpImageFiles/";//数据库中记录的文件夹地址  
                url = fp + newname;//服务器文件地址  
                urlsql = fpsql + newname;//服务器中记录的文件地址  

                var urldel = jurl + fod + newname;//图片的绝对路径
                if (System.IO.File.Exists(Server.MapPath(url)))  
                {  
                    //MessageBox.Show(this, "文件已存在！");  
                    File.Delete(urldel);
                }  
               
                    files.SaveAs(Server.MapPath(url));//上传  
                    string path = Server.MapPath(fp);  
                    //取得文件名(抱括路径)里最后一个"."的索引  
                    int i = fn.LastIndexOf(".");  
                    //取得文件扩展名  
                    string newext = fn.Substring(i);
                    string data = IDCard;//新名称  
                    FileInfo fii = new FileInfo(path + fn);  
                    urlsql = fpsql + data + newext;  
                    string path1 = fp + data + newext;  
                    FileInfo fi1 = new FileInfo(path1);  
                    if (fi1.Exists)  
                    {  
                        fi1.Delete();  
                    }

                }

              
            catch(Exception en)  
            {
                resultStr = "<script> alert('保存失败！" + en.Message + "');</script>";
               // MessageBox.Show(this, "出现错误，请重新上传！");  
            }
            }