Month: May 2007

I’ve never really been happy with how checkbox controls look when contained in Grid columns, displaying logical values. Lately I’ve been using the method described below.

Given a table with a logical column such as:

create cursor FILMLIST values ( VIEWED L, TITLE C(50) )

I use an expression for the grid column instead of referencing the table column name directly:

Alignment=2-(Middle Center)
ControlSource = iif(FILMLIST.VIEWED,"ü"," ")
FontName=Wingdings
FontSize=11
ReadOnly=TRUE

The default textbox control in the column will display the logical value as a tick mark (the WingDings character for ü):

This is all you need to do for a read-only column. For my users, I make the column editable by adding some code to the textbox’s .DblClick() event:

replace FILMLIST.VIEWED with !nvl(FILMLIST.VIEWED,.F.)
this.Refresh()

This toggles the logical flag when the user double-clicks the mouse in the column – and handles possible NULL values as well.

As an exercise for the student, try adding support for toggling the flag using the keyboard SPACE bar.