ADO.NET

Paging in DataGrid Control using ADO.NET


This article has been excerpted from book "A Programmer's Guide to ADO.NET in C#".

The "Paging Property Page" section, the paging page of the Property Builder for the DataGrid lets you set a DataGrid's paging properties. In this example I'll show you how you can write applications with paging and navigate though pages in the DataGrid control. You can set a DataGrid's paging properties in the property Builder at design-time as well as programmatically. In this section I'll walk you though both methods.

Note: To test samples, I'll use the Northwind database 

To test this application, create an ASP.NET Web application and add a DataGrid control to the Web form from the toolbox.

Enabling Paging at Design-Time

You can set paging options at design-time by right-clicking on the DataGrid's properties menu item. The paging page looks like figure 7-48. This page lets you set the number of rows per page and the type of navigation you want to show. If you want to provide your own paging click on the Allow Custom Paging check box.

Figure-7.48.jpg

Figure 7-48. DataGrid paging properties

As you can see from figure 7-48, I set the page size to 5 rows and mode to page Numbers. So, when a browser displays the first page of a table in the DataGrid, it will show five rows. Additionally, it will display page numbers at the button of the page so that users can navigate through the pages. The next step for enabling paging in a data grid is to write a PageIndexChanged event handler. You can add the PageIndexChanged handler from the data grid's properties windows, as shown in figure 7-49.

Figure-7.49.jpg

Figure 7-49. Adding the PageIndexChanged event handler

Now write the code shown in listing 7-10. As you can see, I set DataGrid.CurrentPageIndex as DataGridPageChangedEventArgs's NewPageIndex. VS.NET takes cure of the rest for you.

Listing 7-10. The PageIndexChanged handler of the data grid control

        private void DataGrid1_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
        {
            DataGrid1.CurrentPageIndex = e.NewPageIndex;
            DataGrid1.DataBind();
        }

The next thing I'm going to do is it fill data from a database. Listing 7-11 shows the code that fills the data from the Northwind database on the form load. The code should look familiar. I create a connection and data adapter objects and filled a dataset the Employee table.

Listing 7-11. Source code of DataGrid paging sample

        protected void Page_Load(object sender, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
        {
            // Create a Connection object
            string ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;" +
            "Data Source =c://GuestBook.mdb";
            OleDbConnection conn = new OleDbConnection(ConnectionString);

            // open the connection
            if (conn.State != ConnectionState.Open)
                conn.Open();

            // Create a data adapter
            OleDbDataAdapter da = new OleDbDataAdapter
            ("SELECT ID,Name,Address,Email FROM Guest", conn);

            // Create and fill a dataset
            DataSet ds = new DataSet();
            da.Fill(ds);

            // Bind dataset to the control
            DataGrid1.DataSource = ds;
            DataGrid1.DataBind();

            // Close the connection
            if (conn.State == ConnectionState.Open)
                conn.Close();
        }

Now if you run the program, you'll see that the first page looks like figure 7-50.

Figure-7.50.jpg

Figure 7-50. Paging in the DataGrid

As you can see from Figure 7-50, there are five rows displayed in the grid and there are two pages available. If you click on the 2 link, the result looks like figure 7-51.

Figure-7.51.jpg

Figure 7-51. The second page of DataGrid paging sample

Conclusion

Hope this article would have helped you in understanding Paging in DataGrid Control using ADO.NET. See other articles on the website also for further reference.

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