To determine the Size of the resized control, you can cast the sender parameter of the EventArgs data to a Control and get its Size property (or Height and Width properties individually).
To handle custom layouts, use the Layout event instead of the Resize event. The Layout event is raised in response to a Resize event, but also in response to other changes that affect the layout of the control.
PrivateSub Form1_Resize(ByVal sender As System.Object, ByVal e As System.EventArgs) HandlesMyBase.Resize
Dim myControl As Control
myControl = sender
' Ensure the Form remains square (Height = Width).If myControl.Size.Height <> myControl.Size.Width Then
myControl.Size = New Size(myControl.Size.Width, myControl.Size.Width)
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2