Display SharePoint List Data in a GridView

Display SharePoint List Data in a GridView

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Data;
using Microsoft.SharePoint;
 
namespace SampleProject.DisplayGridView
{
    public partial class DisplayGridViewUserControl : UserControl
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                //Select the current site, assuming the list is in this site.
                SPWeb thisWeb = SPContext.Current.Web;
 
                //Simple query on a Custom List with a column named Filter (Yes/No).
                SPQuery queryList = new SPQuery();
                queryList.ViewFields = "<FieldRef Name='ID' />"
                + "<FieldRef Name='Title' />";
                queryList.Query = "<Where><Eq>"
                + "<FieldRef Name='Filter' />"
                + "<Value Type='Integer'>1</Value>"
                + "</Eq></Where>";
                queryList.ViewFieldsOnly = true;
 
                //The list name is Sample List.
                SPList thisList = thisWeb.Lists["Sample List"];
                SPListItemCollection queryResults = thisList.GetItems(queryList);
 
                //Two columns. I purposely named them differently than their names in the list
                //to prevent confusion & show the difference in this example.
                DataTable dt = new DataTable();
                dt.Columns.Add("Item ID", typeof(int));
                dt.Columns.Add("Item Title", typeof(string));
 
                //Each item in the collection creates a row in the data table.
                if (queryResults.Count > 0)
                {
                    foreach (SPListItem item in queryResults)
                    {
                        DataRow dr = dt.NewRow();
 
                        dr["Item ID"] = item["ID"];
                        dr["Item Title"] = item["Title"] != null ? item["Title"].ToString() : string.Empty;
 
                        dt.Rows.Add(dr);
                    }
                }
                else Label1.Text = "There are no items to display.";
 
                //ID- Notice that I’ve made the Header Text different from both the internal field name
                //and the data table column name. This is what will be displayed.
                BoundField bf = new BoundField();
                bf.DataField = "Item ID";
                bf.HeaderText = "ID #";
                bf.HeaderStyle.HorizontalAlign = HorizontalAlign.Center;
                bf.ItemStyle.HorizontalAlign = HorizontalAlign.Center;
                bf.ItemStyle.Width = Unit.Pixel(50);
                GridView1.Columns.Add(bf);
                //Title- the Header Text is now “Sample Items”.
                bf = new BoundField();
                bf.DataField = "Item Title";
                bf.HeaderText = "Sample Items";
                bf.HeaderStyle.HorizontalAlign = HorizontalAlign.Left;
                bf.ItemStyle.HorizontalAlign = HorizontalAlign.Left;
                bf.ItemStyle.Width = Unit.Pixel(650);
                GridView1.Columns.Add(bf);
 
                //This is the last step, congratulations!
                GridView1.AutoGenerateColumns = false;
                GridView1.DataSource = dt;
                GridView1.DataBind();
            }
        }
    }
}

Hi,
I am not able to view list items in grid view, I am getting blank page web part.
kindly help me on this.
Regards,
Selvan J