[RESOLVED] [2008] TabControl on UserControl - Adding Tabs (Design-time)

[NickThissen]

Hi,


I have a TabControl on a UserControl. I want the UserControl to behave like a TabControl as usual (it contains only the TabControl and a Contextmenu), including Design-time behavior.

I have spent the last two weeks finding out how to add the Design-time behavior and I think I have come a far way.

I finally found a concrete question I can ask you, since I am really stuck on this.



The problem is with adding TabPages during Design-time (while the UserControl is a custom tabcontrol, it is using regular windows forms TabPages).

In the Designer class, I have the following code to add a TabPage:

Dim dh As IDesignerHost = DirectCast(GetService(GetType(IDesignerHost)), IDesignerHost)
 
        If dh IsNot Nothing Then
            Dim i As Integer = tc.SelectedIndex
            Dim name As String = GetNewTabName()
            Dim tab As TabPage = TryCast(dh.CreateComponent(GetType(TabPage), name), TabPage)
            tab.Text = name
            tc.Controls.Add(tab)
            tc.SelectedTab = tab
            RaiseComponentChanging(TypeDescriptor.GetProperties(Control)("SelectedIndex"))
            RaiseComponentChanged(TypeDescriptor.GetProperties(Control)("SelectedIndex"), i, tc.SelectedIndex)
        End If

(tc is an instance of my custom TabControl)

I got this code from another (C#.NET) custom TabControl. The problem here is that with the other C#.NET tabcontrol, the usercontrol IS the tabcontrol.
With me, the usercontrol is a regular usercontrol that CONTAINS a tabcontrol.

The difference might seem small but it is a huge difference when trying to add TabPages (at least I think so)!

As you can see, the code above adds a TabPage by using:

tc.Controls.Add(tab)

In the C# project this works because tc.Controls would mean the tabcontrol collection.

In my project, tc.Controls returns the windows forms TabControl and the Contextmenu. NOT the TabPages!

So, I thought, that would be an easy fix: simply change "tc.Controls" to "tc.tabCtrl.TabPages" (where 'tabCtrl' is the windows forms TabControl).

However, there is one problem: If I do this in the designer, the tabs DO NOT GET ADDED to my custom TabControl!! I can see this easily in the Form Designer file.

With a regular TabControl (TabControl1) after adding two tabpages I get:

'
        'TabControl1
        '
        Me.TabControl1.Controls.Add(Me.TabPage3)
        Me.TabControl1.Controls.Add(Me.TabPage4)
        Me.TabControl1.Location = New System.Drawing.Point(250, 192)
        Me.TabControl1.Name = "TabControl1"
        Me.TabControl1.SelectedIndex = 0
        Me.TabControl1.Size = New System.Drawing.Size(200, 100)
        Me.TabControl1.TabIndex = 1

Note the "Me.TabControl1.Controls.Add" part: this is where the TabPages are added to the TabControl.

Now my custom tabcontrol (CTabControl1):

'
        'CTabControl1
        '
        Me.CTabControl1.Location = New System.Drawing.Point(12, 12)
        Me.CTabControl1.Name = "CTabControl1"
        Me.CTabControl1.SelectedIndex = 1
        Me.CTabControl1.SelectedTab = Me.TabPage2
        Me.CTabControl1.Size = New System.Drawing.Size(200, 186)
        Me.CTabControl1.TabIndex = 0

As you can see, no such thing! The tabpages are not added.


So: I think I HAVE to use 'tc.Controls.Add' but I CAN'T because controls does not refer to the TabPages collection!!

How can I solve this?

I have tried shadowing the Controls collection and returning the TabPages instead of the Controls collection, but then I obviously got errors when the designer tries to add the windows forms TabControl + contexmenu...

I am really clueless... Is this even possible??

Thanks!


EDIT
I had a new idea and was confident that it would work but no...

I tried overriding the 'OnControlAdded' method by doing this:

Protected Overrides Sub OnControlAdded(ByVal e As System.Windows.Forms.ControlEventArgs)
        If TypeOf e.Control Is TabPage Then
            Me.tabCtrl.Controls.Add(CType(e.Control, TabPage))
        Else
            MyBase.OnControlAdded(e)
        End If
    End Sub

So it would add the control to the TabPages collection if it was a TabPage, and use the regular routine otherwise.

(I'm now using 'tc.Controls.Add(tab)' again instead of 'tc.tabCtrl.TabPages.Add')

But, I don't think the designer even gets that far because it is telling me I cannot add TabPages to my usercontrol, because only TabControls can accept TabPages... How can I make my usercontrol understand that it is a TabControl (without Inheriting from a TabControl?)

[NickThissen]

I finally figured it out. Will probably be posting a Codebank entry soon.

[Berkdan]

Could you tell us hot did you make this possible. i really need this.

Thank in advance.

[NickThissen]

Check out the links in my signature, especially this one.