关于上传文件的问题

private void updata_Click(object sender, EventArgs e)
        {
            System.Windows.Forms.OpenFileDialog ofld = new System.Windows.Forms.OpenFileDialog();
            if (ofld.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                string text = ofld.FileName;
         

            

            bool fileIsValid = false;
            //判断文件否符合要求。
            if (this.openFileDialog1.HasFile)
            {
                //获取上传文件的扩展名
                String fileExtension = (this.openFileDialog1.FileName).ToLower();
                String[] restrictExtension = { ".gif", ".jpg", "bmp", "png" };
                //判断文件类型是否符合要求
                for (int i = 0; i < restrictExtension.Length; i++)
                {
                    if (fileExtension == restrictExtension[i])
                    {
                        fileIsValid = true;
                    }
                }
                //如果文件类型符合要求，?调用SaveAs方法实现上传，并显示相关信息
                if (fileIsValid == true) {
                try {
                    this.openFileDialog1.SaveAs(Server.MapPath("~/Picture/") + updataload.FileName);
                    untCommon.InfoMsg ("文件上传成功|！");
                    }catch{
                untCommon.InfoMsg ( "文件上传失败！");
                }
            }else{
            untCommon.InfoMsg ("只能上传指定扩展名.gif,.jpg,.bmp,png的文件");
                 }
           }











求助我用的是Visual Studio 2008进行编程 ，编译的上传文件代码有一部分（HasFile，SaveAs，Server总是说我不包含定义，另外我已经添加好控件了。