Simple Runtime Control Sizing and Dragging Class

Download demo project - 14.4 Kb

Figure - Form showing selected Label control, following selection

Introduction

The PickBox class provides sizing handles that allow the positioning and sizing on simple controls on a containing form. This C# sample was adapted from an earlier version of the class written in VB (version 6). The sample was prepared using Borland's C# Builder IDE and exported to a VS project.

Using the code

The PickBox class exposes a "WireControl" method that attaches events to a passed control, implementing “pickbox” behavior. Clicking on a “wired” control displays eight sizing handles around the perimeter of the control and enables sizing and dragging of the control via mouse event handlers provided by the class instance (see commented code for details). The following snippet illustrates the use of the PickBox class and this function from within the Sample Form:

//(Excerpt from Winform.cs)
//
// Create an instance of the PickBox class
//
private PickBox pb = new PickBox();
public WinForm() // Sample Form's constuctor
{
    InitializeComponent();
    //
    // Provide a Click event handler for each control
    // that attaches a pick box to the control when clicked
    //
    foreach (Control c in this.Controls) {
        pb.WireControl(c);
    }
}

The "WireControl" method attaches a Click event handler to each passed control. When called the event handler then attaches the "pickbox", made up of eight Label controls that act as sizing handles, to the clicked control. In addition, mouse event handlers are attached to the control allowing for dragging of the control on its parent form.

//(Excerpt from PickBox.cs)
private void SelectControl(object sender, EventArgs e) {
    if (m_control is Control) {
        m_control.Cursor = oldCursor;
        // Remove event any event handlers appended to last control
        // by this class
        m_control.MouseDown -= new MouseEventHandler(this.ctl_MouseDown);
        m_control.MouseMove -= new MouseEventHandler(this.ctl_MouseMove);
        m_control.MouseUp -= new MouseEventHandler(this.ctl_MouseUp);
        m_control.Click -= new EventHandler(this.SelectControl);
        m_control = null;
    }
    m_control = (Control)sender;
    //Add event handlers for moving the selected control around
    m_control.MouseDown += new MouseEventHandler(this.ctl_MouseDown);
    m_control.MouseMove += new MouseEventHandler(this.ctl_MouseMove);
    m_control.MouseUp += new MouseEventHandler(this.ctl_MouseUp);
    //Add sizing handles to Control's container (Form or PictureBox)
    for (int i = 0; i<8; i++) {
        m_control.Parent.Controls.Add(lbl[i]);
        lbl[i].BringToFront();
    }
    //Position sizing handles around Control
    MoveHandles();
    //Display sizing handles
    ShowHandles();
    oldCursor = m_control.Cursor;
    m_control.Cursor = Cursors.SizeAll;
}

The sizing handles are Labels that are created, initialized and stored in an array of Label controls when the instance of the PickBox class is constructed. MouseDown, MouseMove, and MouseUp events service the array of Labels during control sizing operations.

Points of Interest

The class sample works well for simple applications, but may exhibit some interaction within applications employing more complicated, time-critical event handling. In it’s current form it provides for the selection of only one control at a time.

The PickBox sample is a simpler, and probably less versatile C# example of the functionality presented in the C++ sample “A Sizing/Moving widget” by Andrew JM Hall.

History

This is the initial submission of the sample.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Jim Korovessis

Program Manager
General Dynamics Canada

Canada

Member

Manager, Customer Training in Ottawa, ON, Canada
www.gdcanada.com

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Nice Article!!!

Irfan Kothari

0:32 11 Apr '07

Hello sir, Thanks a lot, i got exactly what i want.. Really a great article.. Thanks, Irfan "Take Care Not Chances"
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how about rotating ?

The Code Guru

13:25 19 Jan '07

how about impleminting a rotating of the control ? can it be done and how ? Imagination is more important than knowledge... {Albert Einstein}
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Re: how about rotating ?

JK Rajesh

18:59 30 Jan '07

This is exactly what i need too..... i need to place the sizing handles at different rotation angles and add an extra sizing handle to rotate the control....if u hav any code for that then pls do help. Thank you
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Re: how about rotating ?

The Code Guru

20:14 30 Jan '07

i do have some , but i cant give it out since its in commercial product Imagination is more important than knowledge... {Albert Einstein}
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VS 2005

NewbieDude

0:59 7 Feb '06

This project does not run in visual studio 2005, it says it has problems during the conversion process, any help on this issue?
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Re: VS 2005

shitfish

5:03 18 Aug '06

open the csproj file in a text editor and fill in the empty name="" attribute, then it will convert.
Sign In·View Thread·Permalink	2.25/5 (4 votes)

UserControls

dchurch24

0:04 24 Jan '06

Hi, I've been experimenting with this to try and get it to support custom made UserControls, but to no avail. Are there any pointers you can give me?
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Additional code for handling child controls

Ronit H

4:01 31 Oct '05

Hi, The sample code does not work for child controls inside panels etc. Therefore, I have added the following recursive function which maps all controls in a form: public void WireControls(Control _Control) { if (!(_Control is Form)) WireControl(_Control); foreach (Control c in _Control.Controls) { WireControls(c); } } Ronit
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Re: Additional code for handling child controls

heckknow

15:54 2 Jan '07

Anyone know the VC++ 2005 equivalent of Ronit's code?

I've managed to convert Jim Korovessis excellent Simple Runtime Control Sizing and Dragging Class over to VC++ but it doesn't work (builds and runs fine but doesn't show the sizing grab handles). It took me about half a day to complete the conversion.

I think it's because my controls are inside another control. So, I wanted to add Ronit's code to see if that's the case. But VC++ is complaining error C2275 when I changed:

if (!(_Control is Form))

to

if (_Control != Form)

It said 'System::Windows::Forms::Form' is illegal use of this type as an expression. Does anyone know? Thanks.

VB.NET code for us non-C# folks :)

mpemberton

9:03 27 Oct '05

I don't take credit for all of this translation. The reasonably good conversion tool by Kamal Patel[^] did most of it, but I did the rest (and tested). Enjoy...

If anyone else has any additional tweaks to share, such as multi-select for block moving, deleting controls, etc, that would be lovely. I'm just now getting started with a new project and this code was EXACTLY what I was looking for! Thank you very much for sharing your expertise!

Public Class PickBox
    '/ summary
    '/ This class implements sizing and moving functions for
    '/	runtime editing of graphic controls
    '/ summary
    '////////////////////////////////////////////////////////////////
    ' PRIVATE CONSTANTS AND VARIABLES
    '////////////////////////////////////////////////////////////////

    Private Const BOX_SIZE As Integer = 8
    Private BOX_COLOR As Color = Color.White
    Private m_container As ContainerControl
    Private m_control As Control
    Private lbl(8) As Label
    Private startl As Integer
    Private startt As Integer
    Private startw As Integer
    Private starth As Integer
    Private startx As Integer
    Private starty As Integer
    Private dragging As Boolean
    Private arrArrow() As Cursor = New Cursor() {Cursors.SizeNWSE, Cursors.SizeNS, _
Cursors.SizeNESW, Cursors.SizeWE, Cursors.SizeNWSE, Cursors.SizeNS, _
Cursors.SizeNESW, Cursors.SizeWE}
 
    Private oldCursor As Cursor
 
    Private Const MIN_SIZE As Integer = 20
 
    '
    ' Constructor creates 8 sizing handles & wires mouse events
    ' to each that implement sizing functions
    '
    Public Sub New()
        Dim i As Integer
        For i = 0 To 8 - 1 Step i + 1
            lbl(i) = New Label
            lbl(i).TabIndex = i
            lbl(i).FlatStyle = 0
            lbl(i).BorderStyle = BorderStyle.FixedSingle
            lbl(i).BackColor = BOX_COLOR
            lbl(i).Cursor = arrArrow(i)
            lbl(i).Text = ""
            lbl(i).BringToFront()
            AddHandler lbl(i).MouseDown, AddressOf Me.lbl_MouseDown
            AddHandler lbl(i).MouseMove, AddressOf Me.lbl_MouseMove
            AddHandler lbl(i).MouseUp, AddressOf Me.lbl_MouseUp
        Next
    End Sub
 
    '////////////////////////////////////////////////////////////////
    ' PUBLIC METHODS
    '////////////////////////////////////////////////////////////////

    '
    ' Wires a Click event handler to the passed Control
    ' that attaches a pick box to the control when it is clicked
    '
    Public Sub WireControl(ByVal ctl As Control)
        AddHandler ctl.Click, AddressOf SelectControl
    End Sub
 

    '///////////////////////////////////////////////////////////////
    ' PRIVATE METHODS
    '///////////////////////////////////////////////////////////////

    '
    ' Attaches a pick box to the sender Control
    '
    Private Sub SelectControl(ByVal sender As Object, ByVal e As EventArgs)
 
        If TypeOf m_control Is Control Then
            m_control.Cursor = oldCursor
 
            'Remove event any pre-existing event handlers appended by this class
            RemoveHandler m_control.MouseDown, AddressOf Me.ctl_MouseDown
            RemoveHandler m_control.MouseMove, AddressOf Me.ctl_MouseMove
            RemoveHandler m_control.MouseUp, AddressOf Me.ctl_MouseUp
 
            m_control = Nothing
        End If
 
        m_control = CType(sender, Control)
        'Add event handlers for moving the selected control around
        AddHandler m_control.MouseDown, AddressOf Me.ctl_MouseDown
        AddHandler m_control.MouseMove, AddressOf Me.ctl_MouseMove
        AddHandler m_control.MouseUp, AddressOf Me.ctl_MouseUp
        AddHandler m_control.Parent.Click, AddressOf Me.Parent_Click
 
        'Add sizing handles to Control's container (Form or PictureBox)
        Dim i As Integer
        For i = 0 To 8 - 1 Step i + 1
            m_control.Parent.Controls.Add(lbl(i))
            lbl(i).BringToFront()
        Next
 
        'Position sizing handles around Control
        MoveHandles()
 
        'Display sizing handles
        ShowHandles()
 
        oldCursor = m_control.Cursor
        m_control.Cursor = Cursors.SizeAll
 
    End Sub
 
    Public Sub Remove()
        HideHandles()
        m_control.Cursor = oldCursor
    End Sub
 
    Private Sub ShowHandles()
        If Not m_control Is Nothing Then
            Dim i As Integer
            For i = 0 To 8 - 1 Step i + 1
                lbl(i).Visible = True
            Next
        End If
    End Sub
 
    Private Sub HideHandles()
        Dim i As Integer
        For i = 0 To 8 - 1 Step i + 1
            lbl(i).Visible = False
        Next
    End Sub
 
    Private Sub MoveHandles()
        Dim sX As Integer = m_control.Left - BOX_SIZE
        Dim sY As Integer = m_control.Top - BOX_SIZE
        Dim sW As Integer = m_control.Width + BOX_SIZE
        Dim sH As Integer = m_control.Height + BOX_SIZE
        Dim hB As Integer = BOX_SIZE / 2
        Dim arrPosX = New Integer() {sX + hB, sX + sW / 2, sX + sW - hB, _
            sX + sW - hB, sX + sW - hB, sX + sW / 2, sX + hB, sX + hB}
 
        Dim arrPosY = New Integer() {sY + hB, sY + hB, sY + hB, sY + sH / 2, _
            sY + sH - hB, sY + sH - hB, sY + sH - hB, sY + sH / 2}
 
        Dim i As Integer
        For i = 0 To 8 - 1 Step i + 1
            lbl(i).SetBounds(arrPosX(i), arrPosY(i), BOX_SIZE, BOX_SIZE)
        Next
    End Sub
 
    '///////////////////////////////////////////////////////////////
    ' MOUSE EVENTS THAT IMPLEMENT SIZING OF THE PICKED CONTROL
    '///////////////////////////////////////////////////////////////

    '
    ' Store control position and size when mouse button pushed over
    ' any sizing handle
    '
    Private Sub lbl_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs)
        dragging = True
        startl = m_control.Left
        startt = m_control.Top
        startw = m_control.Width
        starth = m_control.Height
        HideHandles()
    End Sub
 
    '
    ' Size the picked control in accordance with sizing handle being dragged
    '	0   1   2
    '   7       3
    '   6   5   4
    '
    Private Sub lbl_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
        Dim l As Integer = m_control.Left
        Dim w As Integer = m_control.Width
        Dim t As Integer = m_control.Top
        Dim h As Integer = m_control.Height
        If dragging Then
            Select Case (CType(sender, Label)).TabIndex
                Case 0
                    ' Dragging top-left sizing box
                    If startl + e.X < startl + startw - MIN_SIZE Then
                        l = startl + e.X
                    Else
                        l = startl + startw - MIN_SIZE
                    End If
                    If startt + e.Y < startt + starth - MIN_SIZE Then
                        t = startt + e.Y
                    Else
                        t = startt + starth - MIN_SIZE
                    End If
 
                    w = startl + startw - m_control.Left
                    h = startt + starth - m_control.Top
                    Exit Select
                Case 1
                    ' Dragging top-center sizing box
                    If startt + e.Y < startt + starth - MIN_SIZE Then
                        t = startt + e.Y
                    Else
                        t = startt + starth - MIN_SIZE
                    End If
                    h = startt + starth - m_control.Top
                    Exit Select
                Case 2
                    ' Dragging top-right sizing box
                    If startw + e.X > MIN_SIZE Then
                        w = startw + e.X
                    Else
                        w = MIN_SIZE
                    End If
                    If startt + e.Y < startt + starth - MIN_SIZE Then
                        t = startt + e.Y
                    Else
                        t = startt + starth - MIN_SIZE
                    End If
                    h = startt + starth - m_control.Top
                    Exit Select
                Case 3
                    ' Dragging right-middle sizing box
                    If startw + e.X > MIN_SIZE Then
                        w = startw + e.X
                    Else
                        w = MIN_SIZE
                    End If
                    Exit Select
                Case 4
                    ' Dragging right-bottom sizing box
                    If startw + e.X > MIN_SIZE Then
                        w = startw + e.X
                    Else
                        w = MIN_SIZE
                    End If
                    If starth + e.Y > MIN_SIZE Then
                        h = starth + e.Y
                    Else
                        h = MIN_SIZE
                    End If
                    Exit Select
                Case 5
                    ' Dragging center-bottom sizing box
                    If starth + e.Y > MIN_SIZE Then
                        h = starth + e.Y
                    Else
                        h = MIN_SIZE
                    End If
                    Exit Select
                Case 6
                    ' Dragging left-bottom sizing box
                    If startl + e.X < startl + startw - MIN_SIZE Then
                        l = startl + e.X
                    Else
                        l = startl + startw - MIN_SIZE
                    End If
                    w = startl + startw - m_control.Left
                    If starth + e.Y > MIN_SIZE Then
                        h = starth + e.Y
                    Else
                        h = MIN_SIZE
                    End If
                    Exit Select
                Case 7
                    ' Dragging left-middle sizing box
                    If startl + e.X < startl + startw - MIN_SIZE Then
                        l = startl + e.X
                    Else
                        l = startl + startw - MIN_SIZE
                    End If
                    w = startl + startw - m_control.Left
                    Exit Select
            End Select
            If l < 0 Then
                l = 0
            Else
                l = l
            End If
            If t < 0 Then
                t = 0
            Else
                t = t
            End If
            m_control.SetBounds(l, t, w, h)
        End If
    End Sub
 
    '
    ' Display sizing handles around picked control once sizing has completed
    '
    Private Sub lbl_MouseUp(ByVal sender As Object, ByVal e As MouseEventArgs)
        dragging = False
        MoveHandles()
        ShowHandles()
    End Sub
 
    '///////////////////////////////////////////////////////////////
    ' MOUSE EVENTS THAT MOVE THE PICKED CONTROL AROUND THE FORM
    '///////////////////////////////////////////////////////////////

    '
    ' Get mouse pointer starting position on mouse down and hide sizing handles
    '
    Private Sub ctl_MouseDown(ByVal sender As Object, ByVal e As MouseEventArgs)
        dragging = True
        startx = e.X
        starty = e.Y
        HideHandles()
    End Sub
 
    '
    ' Reposition the dragged control
    '
    Private Sub ctl_MouseMove(ByVal sender As Object, ByVal e As MouseEventArgs)
        If dragging Then
            Dim l As Integer = m_control.Left + e.X - startx
            Dim t As Integer = m_control.Top + e.Y - starty
            Dim w As Integer = m_control.Width
            Dim h As Integer = m_control.Height
            If l < 0 Then
                l = 0
            Else
                If l + w > m_control.Parent.ClientRectangle.Width Then
                    l = m_control.Parent.ClientRectangle.Width - w
                Else
                    l = l
                End If
            End If
            If t < 0 Then
                t = 0
            Else
                If t + h > m_control.Parent.ClientRectangle.Height Then
                    t = m_control.Parent.ClientRectangle.Height - h
                Else
                    t = t
                End If
            End If
 
            m_control.Left = l
            m_control.Top = t
        End If
    End Sub
 
    '
    ' Display sizing handles around picked control once dragging has completed
    '
    Private Sub ctl_MouseUp(ByVal sender As Object, ByVal e As MouseEventArgs)
        dragging = False
        MoveHandles()
        ShowHandles()
    End Sub
 
    Private Sub Parent_Click(ByVal sender As Object, ByVal e As EventArgs)
        Remove()
    End Sub
End Class

Mark

Saving Layout

kumagKayo

17:06 22 Aug '05

Nice, I was also looking for this one, how bout saving layout, how would you go about doing that? would you use xml? para saaan naman ito
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Suggestion

Carl Mercier

10:35 11 Jul '05

One feature that you could add would be the ability to double click on controls and change their text property. For example, double click on a label (or GroupBox) and be able to type in the Text property directly in the form. Whenever you have the time, of course Very nice piece of code that you have!
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Works great with my Custom Control + How to Unwire in Run Time

babuntu

12:15 24 Jun '05

Just found out .NET won't let you resize your control in runtime. So how lucky was I to find this great class and add it to my project. Fantastic work!

To unwire or un-select at run-time simply add this event handler in the selectControl method:
m_control.Parent.Click +=new EventHandler(Parent_Click);

And then just add this event handler method where you call the Remove() method already supplied by the class.

private void Parent_Click(object sender, EventArgs e){ Remove(); }

Works!
Jamshed Rahman

Not able to Work with runtime Control and resizing

dvsriram

20:22 18 Sep '07

i created the controls at runtime on panel using toolstrip in vs2005 using vb.net , so if add this it is working on the panel, toolstrip that' all . i am not able to access the runtime control like label1 ,checkbox1,RB1 ,TB1 like that . if i am able to access the control like label1 it is showing the squares but not able to resize the runtime controls , Urgent Help Needed .... D.V.Sriram
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limited to certain controls?

djhart

18:18 8 May '05

Thank you for your post. This is exactly what I need. However, I tried it with a treeview and it didn't work. The control would not select, resize or move. I put another push button on the form and it worked fine. So, I am guessing that the code will only work for certain controls. If I am wrong or there is something I can change to make it work, please let me know. I need it to work with a treeview and a axWebBrowser control. Thank you.

Re: limited to certain controls?

MarkDuncan

3:55 25 Jul '05

Hi,

Firstly thanks to Jim for this great code, its exactly what I'm looking for. I tried this on a RichTextbox and I was having the same problem to fix it all i've done is a minor change to the WireControl

If ctl.GetType.ToString = "System.Windows.Forms.RichTextBox" Then
AddHandler ctl.GotFocus, AddressOf Me.SelectControl
Else
AddHandler ctl.Click, AddressOf Me.SelectControl
End If

and this seems to have done the trick.

PS I've converted the code in VB for my purposes.

Re: limited to certain controls?

MarkDuncan

3:59 25 Jul '05

Scratch that - noticed a few problems. I'll work away at it and I'll post if I get it sorted out
Sign In·View Thread·Permalink	5.00/5 (1 vote)

Increasing productivity

IFreezy

0:37 19 Apr '05

Hello! I was reading your article and found some things that can work slightly faster.
Why to not create event once and then to use repeatedly?
// No

 lbl [i] .MouseDown + = 

           new MouseEventHandler(this.lbl_MouseDown);

// Yes



	 MouseEventHandler _onUp = new MouseEventHandler (this.lbl_MouseUp);

	 for (int i = 0; i <8; i ++) {

		...

		 lbl [i] .MouseDown + = _onDown;

		...

	}



private void SelectControl(object sender, EventArgs e) 

{

	if (this.currMode == Mode.Default)

		return;

	if (m_control is Control) 

	{

		...

		//Remove event any pre-existing event

            //handlers appended by this class

		m_control.MouseDown -= onDown; //this 

            //delegates we created in constructor

		m_control.MouseMove -= onMove; //and this!

		m_control.MouseUp   -= onUp;   //

	}

	//Add event handlers for moving the selected 

      //control around

	m_control.MouseDown += onDown;

	m_control.MouseMove += onMove;

	m_control.MouseUp += onUp;

	...

}

private void lbl_MouseMove(object sender, MouseEventArgs e) {

        ...

	if (dragging) {

	switch (((Label)sender).TabIndex) {

		case 0: // Dragging top-left sizing box

			// Must be: 

			// l = e.X < startw - MIN_SIZE ? startl + e.X : startl + startw - MIN_SIZE;

			l = startl + e.X < startl + startw - MIN_SIZE ? startl + e.X : startl + startw - MIN_SIZE;

			...

	...

}

In your example it would be desirable to make two operating modes: Designer and Default.
These code allows two modes, but productivity of these code isn't fast.



public class Pickbox

{

	public enum Mode {

		Default = 0,

		Designer

	}

	private Mode _currMode = Mode.Default;

	...

	public Mode CurrMode {

		get {

		    return _currMode;

		}

		set {

                    if(value == Mode.Designer) {

			// fires event, that allow to remove 

                  // events of all grasped controls

		    }

		    else {

			// fires event, that allow to setup 

                  //events of all grasped controls

 		    }

		}

	}

}

Probably, you know more suitable way

Re: Increasing productivity

youssef

12:23 29 May '05

Can you sending with your correction please ? youssef
Sign In·View Thread·Permalink	2.00/5 (2 votes)

Re: Increasing productivity

youssef

12:24 29 May '05

Can you sending with your correction the files please ? youssef
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Killed 2 birds w/ one stone

Keyser_WS6

11:25 7 Feb '05

For the past week I had been playing around with DragDrop events in my project to get the desired control "movement" effect working, and I was dreading the complication of implementing "selecting" and resizing. This solved both issues much more efficiently than I would have if I hadn't seen it, and for that I thank you!
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Re: Killed 2 birds w/ one stone

ik2

12:47 7 Feb '05

Thanks for your kind words. I was hoping to polish it a bit more, but unfortunately can't seem to find the time with work to get back to a passtime that I really enjoy. Many thanks to you and others that have commented and have made so many useful suggestions to date.
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Great Control

CCosgrove

19:18 18 Jan '05

This control is great, but for my purposes I had to convert it to VB.NET. While converting, i found out that the line:
if (m_control is Control)

Gave a compiler warning within C#, but in VB.NET, it gives you a warning. If you change it in VB.NET to be m_control = getType(Control), then the selected control will start jumping estatically.

A good way around this is to check to see if the control is actually assigned to anything first. You know that controls that are put into the pickbox will be within the class, so there is no need for checking it. A way that works for VB.NET is to change it so that if the control is not empty, you can unwire the handlers then reassign them using this statement:
if not(m_control is nothing)

I tested it with C# too, so changing it to: if m_control != null, then you will get the same result, plus lose the compiler warning. I know this behavior is within Visual Studio, and it could be different in Borland C#, but i thought this was a good heads up for anyone who is also using this control.

But all and all your control was exactly what i was looking for. Many thanks to you!