弹出gridview链接按钮

这是aspx页面代码

"OnClick = " lnkCustomer ">＂SelectCommand="SELECT DISTINCT [firstname]， [middle lename]， [lastname]， [mobile]， [city]， [title]， [enquirymasterid] FROM [EnquiryMaster]">

*我在gridview的链接按钮后面写了这个代码，但是弹出窗口不显示*w

protected void lnkCustomer(object sender, EventArgs e)
   {
       //Retrieve Customer ID
       LinkButton lnkCustomerID = sender as LinkButton;
       string strCustomerID = lnkCustomerID.Text;
       //Create sql connection and fetch data from database based on CustomerID
       string strConnectionString = ConfigurationManager.ConnectionStrings["connstring"].ConnectionString;
       string strSelect = "SELECT DISTINCT [firstname], [middlename], [lastname], [mobile], [city], [title], [enquirymasterid] FROM [EnquiryMaster] WHERE enquirymasterid = @enquirymasterid";
       SqlConnection sqlCon = new SqlConnection();
       sqlCon.ConnectionString = strConnectionString;
       SqlCommand cmdCustomerDetails = new SqlCommand();        
            cmdCustomerDetails.Connection = sqlCon;
        cmdCustomerDetails.CommandType = System.Data.CommandType.Text;
        cmdCustomerDetails.CommandText = strSelect;
        cmdCustomerDetails.Parameters.AddWithValue("@enquirymasterid", strCustomerID);
       sqlCon.Open();
       //Create DataReader to read the record
        SqlDataReader dReader = cmdCustomerDetails.ExecuteReader();
       GridView2.DataSource = dReader;
        GridView2.DataBind();
        sqlCon.Close();
        modalPopUpExtender1.Show();
}