How to: Split two areas with a bar

Let the user widen a list at the expense of the subform next to it (or enlarge a chart above a table at the expense of the table) by dragging a bar between them.

Requires WKL Forms Object Library 1.23 or later.

Place a WklSplitter in the gap between the two areas. With no settings, it moves the controls that lie alongside it within 20 pixels; FirstControls and SecondControls name the controls explicitly instead. Orientation sets the direction, MinSizeFirst and MinSizeSecond set the limits, and CollapseSide sets the side that a double-click collapses. Position is the bar's offset from its designed position, in twips.

In Design view, choose Form Design › Controls › ActiveX Controls › WKL Splitter, draw a narrow bar in the gap (for example, 0.05 in. wide and as tall as the areas), and name it Split1. The designer ([...] in the Custom row, Splitter page) shows which controls it found on each side. To make the settings in code, for example in Form_Load:

With Me!Split1.Object
    .FirstControls = "lstCustomers"           ' empty: found by position
    .SecondControls = "sfOrders;lblOrders"    ' several controls per side
    .MinSizeFirst = 1500                      ' twips each control keeps on its side
    .MinSizeSecond = 3000
    .CollapseSide = wscFirst                  ' a double click folds the list away
End With

To react to the user, or to move the bar from code:

Private Sub Split1_BeforeSplit(Position As Long, Cancel As Integer)
    If Position > 4000 Then Position = 4000   ' change the new offset, or Cancel = True
End Sub
 
Private Sub cmdWideList_Click()
    Me!Split1.Object.Position = 2000          ' code raises no BeforeSplit/AfterSplit
End Sub

• Controls on the first side (left or top) change their width or height; controls on the second side move their near edge and keep their far edge. Controls beyond the areas stay where they are.
• On an Access form, only controls in the splitter's own section count. Areas found by position must lie alongside the bar: a heading text box above both areas isn't a neighbor.
• Keep the areas anchored at the top left. Access stretches anchored controls without notifying the object model, and the splitter calculates every arrangement from the designed positions.
• Position, Collapsed, and Layout take effect only in Form view. The arrangement is remembered for each Windows user unless AutoSaveLayout is False; see How to: Keep the user's arrangement.
• For more than two areas that should use the whole window, use a single WklDockLayout instead of several splitters.

• API reference: WklSplitter
• WklSplitter and WklDockLayout overview
• A control isn't arranged by the layout