C# 上传图片

 string FuJianName = "";
                string sl = "";
                if (this.fileUploadImg.HasFile)
                {
                    //全名 11aa.jpg
                    string fullFileName = this.fileUploadImg.PostedFile.FileName;
                    FuJianName = System.IO.Path.GetFileName(fullFileName); //文件名称 a.jpg                                        

                    //后缀 .jpg
                    string exName = Path.GetExtension(fullFileName);
                    if (exName.Trim().ToLower().ToString() == ".jpg" || exName.Trim().ToLower().ToString() == ".png" || exName.Trim().ToLower().ToString() == ".gif")
                    {
                        sl = "建档" + txtCName.Value.Trim().ToString() + exName;  //自定义名称
                        string savePath = Server.MapPath("UPimg/NewATT/") + sl;
                        this.fileUploadImg.PostedFile.SaveAs(savePath);
                        // this.fileUploadImg.SaveAs(savePath);
                    }
                    else
                    {
                        Page.RegisterStartupScript("", "<script>f_alert2('warn','请只上传jpg、.gif、.png格式的图片!');</script>");
                        return;
                    }
                }