Use the GridView.UseAccessibleHeader property to specify whether the System.Web.UI.WebControls.GridView control renders its header row in an accessible format. This property is provided to make the control more accessible to users of assistive technology devices. By default, the value of this property is true and the header for the control is rendered using <th> table header cell tags. In addition, a scope="col" attribute is added to the table header to specify that the header applies to all the cells in the column. The default rendering of the <th> element is preserved, rendering text as bold and centered horizontally. Developers can override the style of the <th> element using a cascading style sheet.

If the value of this property is false, the header for the control is rendered using <td> table cell tags.