I have to display the gridview by filtering data in between two dates. When I was running this code the gridview is not displaying. no error message. So give me solution to find the error.

<br />
    I have to display the gridview by filtering data in between two dates.<br />
    When I was running this code the gridview is not displaying.<br />
    no error message.<br />
    So give me solution to find the error.<br />
<br />

using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Data;
    using System.Data.SqlClient;
    using System.IO;
    using iTextSharp.text;
    using iTextSharp.text.pdf;
    using iTextSharp.text.html;
    using iTextSharp.text.html.simpleparser;


   namespace WebApplication1
   {
       public partial class Reporting_Mopdule : System.Web.UI.Page
       {

           protected void Page_Load(object sender, EventArgs e)
           {

             if(!IsPostBack)
             {

               solarDataSet2TableAdapters.tbl_energy_reportTableAdapter state;
               state = new solarDataSet2TableAdapters.tbl_energy_reportTableAdapter();



               DataTable dt = new DataTable();
               dt = state.GetStateDataBy();
               DropDownList1.DataSource = dt;
               DropDownList1.DataTextField = "State";
               DropDownList1.DataValueField = "State";
               DropDownList1.DataBind();


           }

           }
           protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
           {

               solarDataSet2TableAdapters.tbl_energy_reportTableAdapter state;
               state = new solarDataSet2TableAdapters.tbl_energy_reportTableAdapter();



               DataTable dt = new DataTable();
               dt = state.GetClusterDataBy(DropDownList1.SelectedValue);
               DropDownList2.DataSource = dt;
               DropDownList2.DataTextField = "Cluster";
               DropDownList2.DataValueField = "Cluster";
               DropDownList2.DataBind();


       }


           protected void Button1_Click(object sender, EventArgs e)
           {

               DateTime dt1 = Convert.ToDateTime(TextBox1_CalendarExtender.SelectedDate);
               DateTime dt2 = Convert.ToDateTime(TextBox2_CalendarExtender.SelectedDate);

               solarDataSet2TableAdapters.tbl_energy_reportTableAdapter state;
               state = new solarDataSet2TableAdapters.tbl_energy_reportTableAdapter();

               DataTable dt = new DataTable();


               dt = state.GetGridDataBy(DropDownList1.SelectedValue.ToString(), dt1.ToString(), dt2.ToString(), DropDownList2.SelectedValue.ToString());
               GridView1.DataSource = dt;
               GridView1.DataBind();


           }

       }
   }