I am trying to hide all the windows of my app when a users session time's out. That works great; however, when a MessageBox is left open when the app times out the message box still is there. I want to be able to close the message box or at least hide it. I've looked up hwnds and hinstances and I don't quite know if thats what I am looking for to accomplish this. I thought this would be fairly easy as I thought MessageBox inherited from Window and of course it doesn't. And a top of that you cannot create an instance of message box to keep track of it. At this point I am not sure what to actually do or what to actually search for.
I am in the process of trying to figure some stuff out using reflection. I can create an instance of MessageBox using reflection but don't think I can call Show() using an instance.
Short answer: just create your own window that looks like a message box
Long answer:
Message boxes are normal WinAPI windows (they have an HWND and can be manipulated by the native API windowing functions) however they are not WPF windows and don't have an associated Window object.
Since they are normal windows you can get their HWND (using FindWindow/ FindWindowEx/ EnumWindows) and trick them into closing (for example, by simulating a Cancel button click)
However, because message boxes are not designed to be manipulated like that this trick has some nasty pitfalls you have to take care of.
And, because message boxes are so simple and you can easily create a message box clone it's just easier to create the close and not take care of all the message boxes corner cases.