property Column.AllowSort as Boolean
Returns or sets a value that indicates whether the user can sort the column by clicking the column's header.

Boolean A boolean expression that indicates whether the column gets sorted when the user clicks the column's header.
Sorting by a single column in the control is a simple matter of clicking on the column head. Sorting by multiple columns, however, is not so obvious. But it's actually quite easy. First, sort by the first criterion, by clicking on the column head. Then hold the Shift key down as you click on a second heading. Another option is dragging the column's header to the control's sort bar. The SortBarVisible property shows the control's sort bar.  Use the AllowSort property to avoid sorting a column when the user clicks the column's header. Use the SortOnClick property to specify the action that control executes when the user clicks the column's head. The control fires the Sort event when the control sorts a column ( the user clicks the column's head ) or when the sorting position is changed in the control's sort bar. Use the AllowDragging property to specify whether the column's header can be dragged. Use the DefaultSortOrder property to specify the column's default sort order, when the user first clicks the column's header. The HeaderEnabled property enables or disables the control's header (including the control's sort/groupby-bar). If the header is disabled, the user can't resize, sort or drag and drop any column.