How to detect when the mouse leaves the form?

Question

I have a form with a lot of controls on it. How can I detect when the mouse leaves the form? I\'ve tried wiring up a MouseLeave event for every single control and the form

Answer 1

From looking at aygunes.myopenid.com's answer I made this version in Vb.Net that recursive adding MouseLeaveHandlers to all controls on the form and then Use the nice Clientrectangle.Contains(pt) to check if mousecursor is on or out of form. Working like a charm. Cred goes to aygunes.myopenid.com.

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    AddMouseLeaveHandlers()
End Sub
Sub AddMouseLeaveHandlers()
    For Each c As Control In Me.Controls
        HookItUp(c)
    Next
    AddHandler Me.MouseLeave, AddressOf CheckMouseLeave
End Sub
Sub HookItUp(ByVal c As Control)        
    AddHandler c.MouseLeave, AddressOf CheckMouseLeave
    If c.HasChildren Then
        For Each f As Control In c.Controls
            HookItUp(f)
        Next
    End If
End Sub
Private Sub CheckMouseLeave(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim pt As Point = PointToClient(Cursor.Position)
    If ClientRectangle.Contains(pt) = False Then
        MsgBox("Mouse left form")
    End If
End Sub