Since this is a common requirement for grids, it's better to build a special subclass of the textbox that has the This.Parent.Parent.DblClick() in its DblClick(). Then use that class for each grid column, and you won't have to remember to duplicate this code in each textbox.
>
>Put your code in the Grid.DblClick method. Now you need to put a reference to that in all the places you need it. For Example:
>
>In each columns' TextBox.DblClick you'd put
this.Parent.Parent.DblClick()>
>The TextBox has as it's Parent the Column, which has as it's Parent the Grid.
>
>If you need it on the Header, you'd do a similar thing, but you only need 1 parent reference,
this.Parent.DblClick()>
>HTH.