CODEWITHSUNDEEP
vb.netinheritance
Brian Hooper
Brian Hooper

Reputation: 22044

Can one move controls around in a form class derived from another form?

I have created a forms which are derived from another form thus:-

Public Class MyForm
    ' ...etc
End Class

Public Class MyDerivedForm
    Inherits MyBaseForm
    ' ...etc
End Class

Public Class MyOtherDerivedForm
    Inherits MyBaseForm
    ' ...etc
End Class

This works quite nicely and I can add controls to the derived form using the form designer. But I'd like to move some of the inherited controls around a bit on MyDerivedForm without disturbing MyBaseForm or MyOtherDerivedForm. I can't see any way of doing this on the forms designer.

Is it possible to do this (preferably with the designer but with code if necessary)?

Upvotes: 0

Views: 1144

Answers (2)

Hans Passant
Hans Passant

Reputation: 941267

This is not a typical VB.NET problem so not so sure what's going on here. You'll get the lock icon on the inherited controls and a grayed-out Properties window for an inherited control when the Modifiers property of the control in the base class is Private. The Winforms designer observes the accessibility of the base class member. Private members can't be messed with. The default value for Modifiers is Friend in VB.NET, Private in C#.

Make it Friend to allow the derived form class to modify the control properties. If the base form class lives in another assembly then Friend isn't good enough, you'll need Public.

The Anchor property can be an issue, but only if you anchor to the right or bottom. The control has a knack for ending up in the wrong spot when the derived form has a different size from the base form if the control is anchored that way. Simply avoided by not anchoring at the right/bottom in the base class and changing the anchor in the derived class.

Upvotes: 1

XN16
XN16

Reputation: 5869

In my VB.NET WinForms application I have inherited forms and I can just grab the inherited controls in the designer and move them about as I would with non-inherited controls on the form.

However I have noticed two things in the past that stop this. If you change the position of the controls on the base form, or change some of the positioning properties (such as anchor or docking), then this can (but not always) move your inherited controls. Also I couldn't move some of my inherited controls in an earlier version of .NET (2.0 I believe), but I never figured out the cause for that so I had to resort to changing the locations via the property grid.

Upvotes: 1

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