Oh....nevermind, you are using that older logic on the window handles being stored off in the collection...gotcha.  I will see if I can reproduce.

Since we no longer use this logic I hadn't noticed that Vista changes the handle several times through the life of the form.  So to get around this, if you still intend to use window handle, then you will need to override the OnHandleChanged method to trap that event so that you can update your collection logic.

However, I would recommend against using the window handle at this point and add a Guid property to your BaseForm that uniquely identifies the form:

Then you can enumerate the Forms collection of the MDI to find your form and then activate it (this code would be referencing the MDI  form):

If you take this approach you will be much safer across multiple platforms and won't be reliant upon the window handle.

Trent, I hate to ask, but using the GUID logic, where is the MyLookupID value coming from?

Edhy Rijo

You would be passing it into some method.  If you look further up the food-chain on this thread, you will see that they have a collection that stores off the open forms.  So when the form is loaded, you would add this guid to the collection with probably a title or something else so that it could be identified in the list (if you are using the panel on the left approach).

In case anyone wants a ToolStripDropDownButton instead of a windowslist in a sidepanel or on a menu you can use this approach.

On the toolstrip i have a button called tsbVinduer so my code on the main form is

Private Sub tsbVinduer_DropDownOpening(ByVal sender As Object, ByVal e As System.EventArgs) Handles tsbVinduer.DropDownOpening

 

        tsbVinduer.DropDownItems.Clear()

 

        For Each f As Form In Me.MdiChildren

 

            Dim item As ToolStripMenuItem = New ToolStripMenuItem(f.Text)

            item.Tag = f

 

            AddHandler item.Click, AddressOf item_Click

 

            tsbVinduer.DropDownItems.Add(item)

        Next

 

    End Sub

 

    Private Sub item_Click(ByVal sender As Object, ByVal e As EventArgs)

 

        Dim item As ToolStripItem = TryCast(sender, ToolStripItem)

        If item IsNot Nothing Then

            Dim f As Form = TryCast(item.Tag, Form)

            If f IsNot Nothing Then

                f.Activate()

            End If

        End If

    End Sub

It gives me this result:

/Teddy

Hi Teddy,

Thanks for sharing this approach, it definitely provide ideas on how to get similar results in different ways which is very good, specially when learning .NET.

Edhy Rijo

Just to add another option to this thread you can also handle the Mdi Client Control Added and Removed on your Main MDI Form.

Hi Trent,



My project follows the ideas outlined in this topic by following the StrataFlix example and I would also like to use the LaunchDialog method of the mainform from a "Setup and Configuration" form (strangely also very similar to the PracticeStudio.NET screen shot earlier in this topic) to open a maintenance form as a child form in the main mdi form.



Unfortunately my still limited knowledge of C# wont let me alter the above VB code to a C# version so any help on doing this would be great.



Cheers,

Keith

Hooray, I've had some success! Maybe I should get up at 2am more often.



So, now my question is, is this the best way of doing this?







Cheers,

Keith

That will work fine