gridview binding ASP.net c#

<asp:GridView ID="GridView1" runat="server">
         <Columns>
                <asp:BoundField DataField="tran_date" HeaderText="Transaction Date"
                    SortExpression="tran_date" />
                <asp:BoundField DataField="RSQ" HeaderText="Transaction Cash"
                    SortExpression="RSQ" />
                <asp:BoundField DataField="RSU" HeaderText="Cash Unit"
                    SortExpression="RSU" />
                <asp:BoundField DataField="CSQ" HeaderText="Credit sale"
                    SortExpression="CSQ" />
                <asp:BoundField DataField="CSU" HeaderText="Credit Unit"
                    SortExpression="CSU" />
                     <asp:BoundField DataField="iAmount" HeaderText="Amount"
                    SortExpression="iAmount" />
            </Columns>
        </asp:GridView>

public void fillgrid()
   {
       conns();
       SqlConnection con=new SqlConnection (conn);
       SqlCommand com;
       try
       {
           con.Open();
           com = new SqlCommand("usp_Dailysales_main", con);
           com.CommandType = CommandType.StoredProcedure;

           com.Parameters.AddWithValue("@FrmDate", DateTime.Parse(rdpFrom.SelectedDate.Value.ToString("yyyy/MM/dd"), CultureInfo.CreateSpecificCulture("en-CA")));
           com.Parameters.AddWithValue("@todate", DateTime.Parse(rdpTo.SelectedDate.Value.ToString("yyyy/MM/dd"), CultureInfo.CreateSpecificCulture("en-CA")));

           //com.Parameters.AddWithValue("@strfltr", strfltr1);
           //   com.Parameters.AddWithValue("@sptype", ddlsreturn.SelectedValue);
           com.Parameters.AddWithValue("@ch", Int32.Parse(Convert.ToString(ViewState["ch"])));

           SqlDataAdapter da = new SqlDataAdapter(com);
           DataTable dt = new DataTable();
           da.Fill(dt);
           GridView1.DataSource = dt;
           GridView1.DataBind();


       }
       catch (Exception ex)
       {
       }

   }