[RESOLVED] How can I detect when ParentForm's properties are changing?

Greetings to everyone!!! :wave:


I am working on a couple of UserControls lately and this time is a custom TitleBar. What I want to do is to detect when ParentForm's properties (like ControlBox for example) is changing by developer in Design Time and then update my TitleBar.

So I added a Timer into my UserControl to do this "work". It works, but I think this isn't the most appropriate approach...

vb.net Code:

Private Sub Timer_Tick(sender As Object, e As EventArgs) Handles Timer.Tick     Me.ControlBox = Me.ParentForm.ControlBox
    If ParentForm.ControlBox = True Then ControlsBox_FlowLayoutPanel.Visible = True Else ControlsBox_FlowLayoutPanel.Visible = False
    If ParentForm.MinimizeBox = True Then MinimizeButton_PictureBox.Visible = True Else MinimizeButton_PictureBox.Visible = False
    Me.MinimizeBox = Me.ParentForm.MinimizeBox
    If ParentForm.MaximizeBox = True Then MaximizeButton_PictureBox.Visible = True Else MaximizeButton_PictureBox.Visible = False
    Me.MaximizeBox = Me.ParentForm.MaximizeBox
End Sub

Is there any other way to do that and not by using a Timer? For example, to detect ParentForm's Text property and then update my UserControl's Text, I do something like this...

vb.net Code:

Private WithEvents _ParentForm As Form
 
Protected Overrides Sub OnParentChanged(e As EventArgs)
    MyBase.OnParentChanged(e)
    _ParentForm = Me.ParentForm
    Call ParentForm_TextChanged()
End Sub
 
Private Sub ParentForm_TextChanged() Handles _ParentForm.TextChanged
    If _ParentForm Is Nothing Then
        FormTitle_Label.Text = FormTitle_Label.Text
    Else
        FormTitle_Label.Text = _ParentForm.Text
    End If
    Invalidate()
End Sub

Is there anything similar for properties like ControlBox, MinimizeBox and MaximizeBox?

Thank you in advance!!!

Question is updated!!!

Not reliably ... the problem is that there is no changed event for the stuff you listed...

The property grid uses the PropertyDescriptors to change properties ... so I though I could hook into those in design time...
However in design the ValueChanged is not triggered???

Kris

Well, here is an example on how we can detect when ParentForm's properties are changing and then do our stuff...

vb.net Code:

Private WithEvents _ParentForm As Form
 
Protected Overrides Sub OnParentChanged(e As EventArgs)
    MyBase.OnParentChanged(e)
    _ParentForm = Me.ParentForm
    Call ParentForm_TextChanged()
    Call ParentForm_StyleChanged()
End Sub
 
Private Sub ParentForm_TextChanged() Handles _ParentForm.TextChanged
    If _ParentForm IsNot Nothing Then FormTitle_Label.Text = _ParentForm.Text
    Invalidate()
End Sub
 
Private Sub ParentForm_StyleChanged() Handles _ParentForm.StyleChanged
    If _ParentForm IsNot Nothing Then
        If _ParentForm.ControlBox = True Then ControlsBox_FlowLayoutPanel.Visible = True Else ControlsBox_FlowLayoutPanel.Visible = False
        If _ParentForm.MinimizeBox = True Then MinimizeButton_PictureBox.Visible = True Else MinimizeButton_PictureBox.Visible = False
        If _ParentForm.MaximizeBox = True Then MaximizeButton_PictureBox.Visible = True Else MaximizeButton_PictureBox.Visible = False
    End If
End Sub

It seems to me that the above code doesn't do what you claim it does. The user could change the Form's properties such as Text or ControlBox over and over again, but the custom title bar won't change until its OnParentChanged sub is called. And when do you do that? The only way to trigger OnParentChanged in the Designer is to delete the existing custom title bar (if any) and add a new one.

I think it would be better to do it the reverse way. In other words, define (or override) Text, ControlBox etc. as properties of the custom title bar. You could then use the Set clauses of these properties to change the corresponding parent form properties.

BB