[2005] Checkbox Checkstate

[SanderK]

Hello,

When changing the .Checked or .CheckState property of a checkbox control in runtime, the CheckBox_CheckedChanged event is automatically called, for obvious reasons which I completely understand. Still, is there a way to somehow not let it do this?

[vbasicgirl]

As you know, thats exactly what its for, what are you trying to do ?

Casey.

[SanderK]

I'm using the checkboxes as a list for tools. I'm working on a simple tile editor and I have these tools like pencil, color picker etc. I'm using checkboxes with appearance = button and with an image, no text. It's easy this way to see which is selected, and I don't need to create 2 different images or something for when the tool is selected.

So, when one of the checkboxes is clicked, I also need to uncheck the previously selected tool. When doing this, its checkedChanged event is called, which is not what I want.

[vbasicgirl]

If i understand you correctly, why dont you run the code in the mouseclick event so you know the user is actually selecting the checkbox and its not being deselected by code, even better, so you dont have to deselect the others is to use radiobuttons with the same appearance.


Casey.

[SanderK]

Thanks. I somehow never thought of using radiobuttons for this; neither did I think of using the Click event. Probably because the default event it opened was the checkChanged one.

Thanks a lot for your help, much appreciated

Now, there's something else that's bothering me. I think it has something to do with the focus of a control. Let me explain this through images.

Pencil Tool is selected;

I select the Picker Tool;

I use it; the Pencil Tool is automatically selected;


There's my problem; the Picker Tool contains a blue rectangle around the image, probably because it still has focus or something. It goes away when I click on either of the buttons.

I don't want these controls to be able to get the focus anyway. I looked into the Active, ActiveControl, Focus and Selectable properties of the control, but the radiobutton (or the checkbox) does not seem to have these properties.

What do I do?

[jmcilhinney]

You can't prevent the standard controls from accepting focus. You have to inherit the class of interest (e.g. Button, CheckBox, RadioButton) and add code to prevent it. It just so happens that I've done that myself for a recent project. Here's one I prepared earlier:

''' <summary>
''' A radio button control that cannot receive focus.
''' </summary>
Public Class UnselectableRadioButton
    Inherits System.Windows.Forms.RadioButton
 
#Region " Constructors "
 
    ''' <summary>
    ''' Initialises a new instance of the <see cref="UnselectableRadioButton"/> class.
    ''' </summary>
    Public Sub New()
        MyBase.New()
 
        'The radio button cannot receive focus.
        Me.SetStyle(ControlStyles.Selectable, False)
    End Sub
 
#End Region 'Constructors
 
#Region " Methods "
 
    Protected Overrides Sub OnClick(ByVal e As System.EventArgs)
        MyBase.OnClick(e)
    End Sub
 
#End Region 'Methods
 
End Class

Once you add that class to your project and build it will appear in your Toolbox, so you can add instances to forms just as you do regular RadioButtons. You don't have to remove the regular RadioButtons you already have though. You can open the designer code file for your form and just do a Find & Replace to replace "System.Windows.Forms.RadioButton" with "UnselectableRadioButton".