Transparent Mdi

[errorfunktion]

Hi, I want to design an Mdi application but with a transparent background for the MdiClient container (and form). It should behave in a similar fashion to the way "Mathematica" behaves if you know that software. I have two screens. I want various child forms to be scattered across both screens but at the same time windows from a different application must be visible, and respond to mouse events, in screen areas where there are no child forms. Put it another way the MdiClient container must fill both screens but be transparent. The problem is that the class MdiClient in non inheritable and I can not override the appropriate method to not color the background. Setting transparentkey in the main form to some color and setting the MdiClient background to this color doesn't work either, the MdiClient control doesn't support transparent background colors. If you have a different idea how I can achieve this functionality that's fine by me. My desire is simply to able to use my screens working area with maximum efficiency and at the same time have the sub forms behave as child forms of a single application. Any help will be most appreciated, Gary

[Tom Deketelaere]

I'm not sure but I think the mdiform overrides his color property and sets it back to the default color. I veagly remember trying something like this a few years ago and if I remember correctly I was able to change the color in code. So perhaps you need to set the transparenty color and color of the mdiclient container in code

[errorfunktion]

Nah, using this line of code: mdiclient1.BackColor = Color.Transparent Generates the following exception: "Control does not support transparent background colors" But it works fine for any other color.

[Tom Deketelaere]

then try the following mdiclient1.transparencykey = color.white mdiclient1.backcolor = color.white I'm not sure what will happen. I think you mdi container will just disapear unless there is a form in it which doesn't have its backcolor set to white (once again it's been a few years since I experimented with it so it's a bit vage)

[Dave Kreskowiak]

You can't do what you want. The MdiClient container does not support a Transparent background, nor does the form hosting it. It can probably be done. You'll have to create your own Form class to support this stuff, complete with how to setup your own window and custom drawing code to show it. You'd better have a thorough knowledge of how Window's windows work, especially Layered Windows. And you'll have to do a bunch of trial-and-error work to get it correct. You're treading in undocumented territory, so you won't be getting much, if any, help on exactly how to pull this off. I hope you can do your own research.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007

[errorfunktion]

Well, I know for sure it has been done. I got the inspiration for this from "Mathematica". But no, there's no way I can pull this off myself, I don't have the knowledge. I will find a way to work around this. Thanks

[Dave Kreskowiak]

Mathematica doesn't use Windows Forms. It uses custom coded windows that do NOT have the weight of the .NET Framework Form class on top of it. It's kind of like making your own chocalate chip cookies from scratch. You know, grinding the flour yourself, making the chocolate chips, raising chickens to lay the eggs you need, ... And then there's the .NET Framework Form class, where you just pull a ready-made cookie out of a bag.

A guide to posting questions on CodeProject[^]
Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007

[errorfunktion]

I know. Kudos on the cookie analogy.;)