I'm trying to create a WPF window that will encompass the entire Desktop working area. In WinForms I'd do this by getting the Union of all the bounds in System.Windows.Forms.Screen.AllScreens.
Is there an equivalent type or other mechanism to get the bounds of the entire desktop in WPF or do I need to use the WinForms type?
Just use WinForms. I do not think there is a direct WPF equivalent.
You could try SystemParameters.VirtualScreenWidth and associated parameters. That might not provide as good as a result as continuing with the WinForms API.
The only downside I can see with the WinForms type is an extra dependency and the larger working set related to that.
Try SystemParameters.VirtualScreen* (Top, Left, Height, and Width) properties. http://msdn.microsoft.com/en-us/library/system.windows.systemparameters.virtualscreenheight(v=VS.100).aspx
Don't use winforms api because it doesn't take into account the fact that WPF's measurement units are not pixels. I came across this issue just recently because I'm losing my vision and have my monitor set to a higher dpi. The codebase I was working on used the Winforms Settings and the UI was larger than my screen.
If you're going to use the winforms api. Look at this blog post on calculating the DPI factor.