Can I replace WM_PAINT with paint eventergs or something different?

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I am close to making an embedded control to my listview. Right now the only obstacle is using a 64x painting solution.

here is the code I am using now:

 Private Const WM_PAINT As Integer = &HF
Protected Overloads Overrides Sub WndProc(ByRef m As Message)
            Select Case m.Msg
                Case WM_PAINT
                    Dim rc As Rectangle
                    For Each ec As EmbeddedControl In _embeddedControls
                        rc = Me.GetSubItemBounds(ec.Item, ec.Column)
                        ec.Control.Bounds = rc
                    Next
                    Exit Select
            End Select
            MyBase.WndProc(m)
        End Sub

I have thought about using:

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
           Select Case e.Graphics
               Case
           Dim rc As Rectangle
                   For Each ec As EmbeddedControl In _embeddedControls
                       rc = Me.GetSubItemBounds(ec.Item, ec.Column)
                       ec.Control.Bounds = rc
                   Next
                End Select


           MyBase.OnPaint(e)
       End Sub

The issue I am having is I do not understand what WM_PAINT is other than it has a 32bit system usage and not a 64 bit, which is what my program is built in.

What I have tried:

I have built a paint event, however, I am not sure what to make the case for it to refer to.

Posted 10-May-18 17:59pm

Member 11856456

Updated 13-May-18 17:42pm

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2 solutions

Solution 1

WM_PAINT is the message that tells windows to draw your control. A VB.NET control should not have any real use for it. There's no reason I can see for it not to fire in a 64 bit environment, your controls are being drawn.

Control.Paint Event (System.Windows.Forms)[^]

This is the .NET equivalent, which I think is the same as what you said. Just use the .NET version unless you need interop.

Posted 10-May-18 18:28pm

Christian Graus

Comments

Member 11856456 11-May-18 0:41am

I had seen this post originally and that is what gave me the idea to use a paint event instead. However, I am still having issues with how to approach what should be in the case portion.

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
Dim blackPen As New Pen(Color.Black, 3)

Select Case e.Graphics
Case
Dim rc As Rectangle
For Each ec As EmbeddedControl In _embeddedControls
rc = Me.GetSubItemBounds(ec.Item, ec.Column)
ec.Control.Bounds = rc
Next
e.Graphics.DrawRectangle(blackPen, rc.X, rc.Y, rc.Width, rc.Height)
End Select

' Draw rectangle to screen.

MyBase.OnPaint(e)
End Sub

This should hoepfully replace the old method for the 32 bit system. any suggestions?

Richard Deeming 11-May-18 9:50am

You don't need anything in the "case" part; you just need to remove the Select Case from that code.

You'll probably also want to move the DrawRectangle call inside the loop.

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
    Dim rc As Rectangle
    Dim blackPen As New Pen(Color.Black, 3)
    
    For Each ec As EmbeddedControl In _embeddedControls
        rc = Me.GetSubItemBounds(ec.Item, ec.Column)
        ec.Control.Bounds = rc
        
        e.Graphics.DrawRectangle(blackPen, rc.X, rc.Y, rc.Width, rc.Height)
    Next
    
    MyBase.OnPaint(e)
End Sub

Member 11856456 11-May-18 9:59am

it's not embedding the control like the WM_PAINT was doing. This should have worked as an equivalent.

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Member 11856456 · Accepted Answer · 2018-05-13T17:43:00

After many hours of searching I finally figured out that a regular paint eventargs was not what I needed. Apparently, I needed a protected overrides using a subitem draw event.

Protected Overrides Sub OnDrawSubItem(ByVal e As System.Windows.Forms.DrawListViewSubItemEventArgs)

      Dim rc As Rectangle
      For Each ec As EmbeddedControl In _embeddedControls
          rc = Me.GetSubItemBounds(ec.Item, ec.Column)
          ec.Control.Bounds = rc
      Next

      With e.Graphics
          .DrawLines(New Pen(SystemColors.ButtonShadow), New Point() {New Point(e.Bounds.Left, e.Bounds.Top - 1), New Point(e.Bounds.Left + e.Bounds.Width, e.Bounds.Top - 1), New Point(e.Bounds.Left + e.Bounds.Width, e.Bounds.Top + e.Bounds.Height), New Point(e.Bounds.Left, e.Bounds.Top + e.Bounds.Height)})
      End With

      e.DrawText()

      MyBase.OnDrawSubItem(e)

  End Sub

This still didnt solve my CPU issue, however, the reference to the 32bit dll is removed and the WM_paint event has now been replaced.