Asp.Net Program for Display table values from database by using gridview?

public void BindGrid()
        {
            using (SqlConnection con = new SqlConnection("ConnectionString"))
            {
                SqlCommand cmd = new SqlCommand()
                {
                    Connection = con,
                    CommandText = "StoreProcedureName/sqlquery",
                    CommandType = CommandType.StoredProcedure//if your commandtext containts SP Name else use CommandType.Text
                };
                //if required add parameter like cmd.Parameters.Add
                cmd.Connection.Open();
                SqlDataReader rdr = cmd.ExecuteReader();
                DataTable _dt = new DataTable();
                _dt.Load(rdr);
                //before binding your gridview load xml file from DataTable
                System.IO.StringWriter _writer = new System.IO.StringWriter();
                _dt.WriteXml(_writer, XmlWriteMode.WriteSchema, false);
                string _result = _writer.ToString();
                //'_gridview' is id of your Gridview
                _gridview.DataSource = _dt;
                _gridview.DataBind();
            }
        }

SqlConnection Conn = new SqlConnection("YourConnectionString");
SqlDataReader rdr = null;
string commandString = "SELECT * FROM YourTableName";

try
{
       Conn.Open();
       SqlCommand Cmd = new SqlCommand(commandString, Conn);
       rdr = Cmd.ExecuteReader();

       YourGridId.DataSource = rdr;
       YourGridId.DataBind();
}
catch (Exception ex)
{
     // Log error
}
finally
{
    if (rdr != null)
    {
        rdr.Close();
    }
    if (Conn != null)
    {
        Conn.Close();
    }
 }