Can't use transition; 'Object reference not set to an instance of an object.'

[JamDoggie]

So basically I can't use transitions without the program instantly crashing with the very undescriptive error in the title, pointing at the DoubleTransition. Am I doing something wrong?

Steps to reproduce:

• Create a blank Avalonia project on latest version, with Visual Studio 2019
• Replace the "Hello Avalonia" text with this:

<Button Content="Test" HorizontalAlignment="Center">
    <Button.Transitions>
      <DoubleTransition Property="Opacity" Duration="0:0:0.2"/>
    </Button.Transitions>
  </Button>

Any thoughts?

[maxkatz6]

<Button Content="Test" HorizontalAlignment="Center">
    <Button.Transitions>
      <Transitions>
         <DoubleTransition Property="Opacity" Duration="0:0:0.2"/>
      </Transitions>
    </Button.Transitions>
  </Button>

[JamDoggie]

..unless I was reading them wrong

[maxkatz6]

Thanks, updated new docs page
https://docs.avaloniaui.net/docs/animations/transitions

[JamDoggie]

Woah! I'm not sure that comes up on google, that's a much nicer looking set of docs!

[danwalmsley]

@kekekeks we need to fix that in xaml compiler.

[maxkatz6]

@danwalmsley I think there is bigger related issue. It might not be possible for compiler to understand, what exactly it should do - add new transitions or create new array of them.
#4464