ListBox.HeadingIndex
From Xojo Documentation
Property (As Integer )
aListBox.HeadingIndex = newIntegerValue
or
IntegerValue = aListBox.HeadingIndex
Supported for all project types and targets.
or
IntegerValue = aListBox.HeadingIndex
Supported for all project types and targets.
Allows you to get and set the sort column in a ListBox. The first column is numbered zero.
Notes
Using this property sets the sort direction indicator in the header.
You can also sort a ListBox by using the SortedColumn property to set the sort column and the ColumnSortDirection property to set the direction of the sort. Then call the Sort method to do the sort.
Example
This code in the Open event of a ListBox sorts on the first column: