vMix supports the use of custom WPF User Controls compiled into an assembly.
Custom User Controls can implement the vMixWPFUserControl interface from the vMixInterop.dll in the vMix installation directory.
This interface allows vMix to communicate with the User Control and gather duration and position information.
1. First make sure the user control has been compiled as a DLL and follows the implementation guidelines above.
2. Click Add Input in vMix and then select the Title / XAML tab
3. Click Browse and browse for the DLL file and click OK
4. Click OK and the control will now be available in vMix.
5. If you have built custom properties through the ShowProperties function, this can be displayed through a right click menu: