Visual Basic 2017: how make usercontrol transparent?

[joaquim]

we can change the usercontrol backcolor to Transparent, but when we add a button(another control) on back, we can't see it.
so how we can make it transparent?
the best and slow way is using Regions?

[ident]

So you want a transparent usercontrol, but want the button visible?

[joaquim]

So you want a transparent usercontrol, but want the button visible?

yes, i need the transparent usercontrol(like a bitmap shaped control) and see the button

[boops boops]

When you put a UserControl on a form, the form becomes the Parent of the UserControl. "Transparent" means "show my Parent's background". So if you set the UC's backcolor to Transparent, you can see the form's background, but not other controls through the transparent parts. That's how transparency works in Windows Forms.

There are several ways to get round this, but it depends on what effect you are looking for. Some possibliities I can think of are:
1. put the Button on the UC instead of on the Form.
2. use Regions to punch holes in the UC so the form's controls will show through. It sounds like you know how to do this. I don't know why it must be slow, but it's always possible to code things badly enough.
3. Do the same as in 2, but use the form's TransparencyKey to make the holes in the UC.
4. use an Owned Form instead of a UserControl and set its BackColor and Opacity to whatever values you like. You can make a form an Owned Form by showing it with Show(Me).
5. use a WPF Window (see "shaped form" in my signature).
... and possibly other things too.

BB

[joaquim]

3 - on UC and Form too lol
2 - maybe you have right, i'm opened to suggestions... tell me the best way for get a Region from a bitmap?

[boops boops]

3 - on UC and Form too lol

You are right, I forgot that.

2 - maybe you have right, i'm opened to suggestions... tell me the best way for get a Region from a bitmap?

I don't understand that question. What bitmap? What does that have to do with a button on the form? Do you mean some colours on a bitmap have to become transparent? Please don't assume I have read all your other threads. Perhaps you could post an image to show your bitmap and the effect you want to get. Or try to describe it better in words.

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[joaquim]

i mean making regions from images

[boops boops]

If you can get an outline of the image as a sequence of points (i.e. a polygon) you can convert that to a GraphicsPath and then to the Region property of a control. To get the outline, you need the Marching Squares algorithm: see here for an example.

BB