How to change MaterialDesign PopupBox PlacementMode via Binding?

[ojonasplima]

Hi!

I have a PopupBox inside a UserControl and I want, based on a condition, change the PlacementMode via a Binding on a property defined inside of the UserControl. After I set the property, the Binding appears to work but for some reason the default placement is set on the PopupBox. Someone have an idea what is the issue? FIY: If I manually set the PlacementMode, it works normally.

Here is the XAML of the Popup with the Binding:

Here is the Property inside my UserControl class:

Thank you for any insight.

[nicolaihenriksen]

@ojonasplima I would assume it is because your SideBar.PlacementMode property is just a normal property and thus any changes to it are not propagated to the target of the binding; effectively turning it into a one-time binding.

You can either implement SideBar.PlacementMode as a DependencyProperty, or you could have SideBar implement the INotifyPropertyChanged interface and invoke the PropertyChanged event in the setter of the PlacementMode property.

I do notice that you have scratched out some things in the screenshot, which potentially could be attributes? If you're using the CommunityToolkit.Mvvm, then you could achieve some of that functionality simply using attributes on a field.

[ojonasplima]

Hi @nicolaihenriksen! Thank you for the answer.
Implementing INotifyPropertyChanged didn't worked also, so I tried with DependencyProperty and worked!