The System.Web.UI.WebControls.TableHeaderScope enumeration is used by the System.Web.UI.WebControls.DataControlFieldHeaderCell and System.Web.UI.WebControls.TableHeaderCell classes to represent the scope of the header cell when it is rendered. The default Scope property for both of these classes is the TableHeaderScope.NotSet value, in which case no HTML scope attribute is written for the header cell. The TableHeaderCell.Scope property is used to make HTML tables more accessible by providing information about relationships between the cells and the headers.