เกิดปัญหา ค่าจากฐานข้อมูลไม่ยอมโชว์ในDataGrid โดยให้เลือกวันจากปฎิทินแล้วไปดึงค่าจากฐานข้อมูลมาโชว์ในDataGrid

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.Drawing;

public partial class _Default : System.Web.UI.Page 
{
    SqlConnection mycn;
    SqlDataAdapter myda;
    DataSet ds = new DataSet();
    DataSet dsSelDate;
    String strConn;


    protected void Page_Load(object sender, EventArgs e)
    {
        // Put user code to initialize the page here
        strConn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        myda = new SqlDataAdapter("Select * FROM EventsTable", strConn);
        myda.Fill(ds, "Table");

    }
    protected void CalendarDRender(object sender, System.Web.UI.WebControls.DayRenderEventArgs e)
    {
        // If the month is CurrentMonth
        if (!e.Day.IsOtherMonth)
        {
            foreach (DataRow dr in ds.Tables[0].Rows)
            {
                if ((dr["EventDate"].ToString() != DBNull.Value.ToString()))
                {
                    DateTime dtEvent = (DateTime)dr["EventDate"];
                    if (dtEvent.Equals(e.Day.Date))
                    {
                        e.Cell.BackColor = Color.PaleVioletRed;
                    }
                }
            }
        }
        //If the month is not CurrentMonth then hide the Dates
        else
        {
            e.Cell.Text = "";
        }
    }

    protected void Calendar1_SelectionChanged1(object sender, EventArgs e)
    {
        //objDatadapter = db.getSqlDataAdapter(data);
        //dataset = new DataSet();
        //objDatadapter.Fill(dataset, "data");
        //GridView_data.DataSource = dataset.Tables["data"];
        //GridView_data.DataBind();


        myda = new SqlDataAdapter("Select * from EventsTable where EventDate='"+ Calendar1.SelectedDate.ToLongDateString() +"'", strConn);
        dsSelDate = new DataSet();
        myda.Fill(dsSelDate, "myda");
        if (dsSelDate.Tables[0].Rows.Count == 0)
        {
            DataGrid1.Visible = false;
        }
        else
        {
            DataGrid1.Visible = true;
            DataGrid1.DataSource = dsSelDate;
            DataGrid1.DataBind();
        }
    }
}