How do I suspend painting for a control and its children?

Question

I have a control which I have to make large modifications to. I\'d like to completely prevent it from redrawing while I do that - SuspendLayout and ResumeLayout aren\'t eno

Answer 1

Here is a combination of ceztko's and ng5000's to bring a VB extensions version that doesn't use pinvoke

Imports System.Runtime.CompilerServices

Module ControlExtensions

Dim WM_SETREDRAW As Integer = 11

''' 

''' A stronger "SuspendLayout" completely holds the controls painting until ResumePaint is called
''' 
''' 
''' 

Public Sub SuspendPaint(ByVal ctrl As Windows.Forms.Control)

    Dim msgSuspendUpdate As Windows.Forms.Message = Windows.Forms.Message.Create(ctrl.Handle, WM_SETREDRAW, System.IntPtr.Zero, System.IntPtr.Zero)

    Dim window As Windows.Forms.NativeWindow = Windows.Forms.NativeWindow.FromHandle(ctrl.Handle)

    window.DefWndProc(msgSuspendUpdate)

End Sub

''' 

''' Resume from SuspendPaint method
''' 
''' 
''' 

Public Sub ResumePaint(ByVal ctrl As Windows.Forms.Control)

    Dim wparam As New System.IntPtr(1)
    Dim msgResumeUpdate As Windows.Forms.Message = Windows.Forms.Message.Create(ctrl.Handle, WM_SETREDRAW, wparam, System.IntPtr.Zero)

    Dim window As Windows.Forms.NativeWindow = Windows.Forms.NativeWindow.FromHandle(ctrl.Handle)

    window.DefWndProc(msgResumeUpdate)

    ctrl.Invalidate()

End Sub

End Module