c# GridView and Paging

I am using gridview to display items from database.When i select an item from dropdownlist the gridview items are displayed.I have enabled paging = true and given the datasource for gridview in dropdownlist_SelectedIndexChanged eventhandler.

When a item is selected the first page items are displayed.But when i go to the second page there are no items being displayed.

I have also used the eventhandler below:

protected void PageChanged(object sender, GridViewPageEventArgs e)

{

this.GridView1.PageIndex = e.NewPageIndex;

this.GridView1.DataBind();

}

What is the problem

Willfin David