CODEWITHSUNDEEP
c#winforms
Immortal Blue
Immortal Blue

Reputation: 1700

transparent tab control appears white

Anyway, I'm having a little difficulty with tab control. When I drag a new tab control onto a form, it appears white, rather than the grey (system colour) I was expecting.

When I look at the properties, its colour is set to web-transparent. Ok, so it should be transparent then (it isn't letting anything behind it show through). Setting the tab control back colour manually back to the system grey kind of works, but the tabs at the top still show as white. I'm assuming I could somehow change their colour as well, but I'm quickly getting into the realms of changing so many values from default, I'm clearly missing something type territory. I've googled every varient of "transparent tab control draws white" as I can, and although I found something to do with windows profiles, this seemed mostly confined to access 2003 using the vb you got access to in access.

I'm looking for any explanation as to:

I'm looking at windows forms for an MCTS, so please don't give a "you should use X instead" type answer.

Upvotes: 2

Views: 5443

Answers (1)

Hans Passant
Hans Passant

Reputation: 942030

No, getting white is certainly normal. TabControl and TabPage are rendered with theme colors when visual styles are enabled. So that makes the tab page white on machines with the standard Windows theme.

Yes, the default BackColor of Transparent is very unusual. You most certainly will never get actual transparency with that, unless you count seeing the background of the TabControl as transparency. The logic is pretty convoluted, rather than trying to explain it I'll just paste the MSDN explanation:

The default value of the BackColor property is the value of the Control.DefaultBackColor property unless the UseVisualStyleBackColor and Application.RenderWithVisualStyles property values are both true and the Appearance property of the parent TabControl has a value of Normal, in which case the default value of the BackColor property is Transparent. Child controls that you place on the TabPage inherit the BackColor value by default, so this behavior causes the background of the child controls to render with the current visual style.

Changing the value of the BackColor property automatically sets the UseVisualStyleBackColor property to false. If you want the TabPage background to render using visual styles but you want the child controls to inherit a BackColor value that you specify, set the UseVisualStyleBackColor property after you set the BackColor property.

Upvotes: 5

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