Gridview - How to Create?

gridview_introduction.aspx.cs

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                BindData();
            }
            
        }
        public void BindData()
        {
		        String connectstring = ConfigurationManager.ConnectionStrings["myConnectionString1"].ConnectionString;
			      SqlConnection con=new SqlConnection(connectstring);
			      DataSet ds = new DataSet();
			      SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "select * from refund_request WHERE orderid=@Value1"; //Query to execute
            cmd.Connection = con;  // Assign the connection to execute the above query
            cmd.Parameters.AddWithValue("@Value1", loginUser); // Provide the input values
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            da.Fill(ds);
            con.Open(); // Open the connection to execute the query
            cmd.ExecuteNonQuery();
            CustomersGridView.DataSource = ds;
            CustomersGridView.DataBind();
            con.Close(); 
        }