Microsoft is a little weird. The safe bet for a desktop application is to do it in WinForms. I'm pretty convinced that Winforms will outlive any of the newer frameworks from Microsoft.
The XAML developers will jump to whatever the next thing is when it comes around, but the conservative WinForm developers won't go anywhere anytime soon, forcing Microsoft to continue supporting and developing Winforms.
Throwing together a quick WinForm application is still much faster than building something using XAML, in my opinion. Especially if you don't know what you're doing, and that still how many in-house business applications seem to be built.
The XAML developers will jump to whatever the next thing is when it comes around, but the conservative WinForm developers won't go anywhere anytime soon, forcing Microsoft to continue supporting and developing Winforms.
Throwing together a quick WinForm application is still much faster than building something using XAML, in my opinion. Especially if you don't know what you're doing, and that still how many in-house business applications seem to be built.