ExecuteNonQuery: CommandText 属性尚未初始化

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
using System.Web.Configuration;
using System.Net;namespace 自由一族后台处理
{
    public partial class quxiaotixing : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string huiyuanid, leixing,weizhangid,sql;
            if (Request.QueryString["huiyuanid"] != null)
            {
                huiyuanid = Request.QueryString["huiyuanid"].ToString();
            }
            else
            {
                huiyuanid = "";
            }
            if (Request.QueryString["leixing"] != null)
            {
                leixing = Request.QueryString["leixing"].ToString();
                //shijian = DateTime.Now.ToLongDateString();
                switch (leixing)
                {
                    case "违章信息提醒":
                        weizhangid = Request.QueryString["weizhangid"].ToString();
                        sql = "insert into [会员信息提醒状态表] (会员编号,违章提醒,取消提醒时间) values ('" + huiyuanid + "','" + weizhangid + "',getdate())";
                        break;
                    case "保险截止日期提醒":
                        sql = "insert into [会员信息提醒状态表] (会员编号,保险截止日期提醒,取消提醒时间) values ('" + huiyuanid + "',1,getdate())";
                        break;
                    case "驾驶证截止日期提醒":
                        sql = "insert into [会员信息提醒状态表] (会员编号,驾驶证截止日期提醒,取消提醒时间) values ('" + huiyuanid + "',1,getdate())";
                        break;
                    default:
                        sql = "";
                        break;                }                SqlConnection objconn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["自由一族ConnectionString"].ConnectionString);
                SqlCommand objCmd = new SqlCommand(sql,objconn);
                //Label1.Text = objCmd.CommandText.ToString();
                
                objconn.Open();
               // objCmd.Connection = objconn;
                objCmd.ExecuteNonQuery();
                objconn.Close();
                Response.Redirect(Request.UrlReferrer.ToString());
                
                //Response.Write(Request.UrlReferrer); 
            }        }
    }
}