Fluent.Button Header Binding not visible

[PJonHar]

I have added a binding to the header property of a fluent.button, however when the application is running the value is not seen?
I have used snoop and i can see that the binding is happy and with the correct value but it does not show?

the value 100 should be showing in the button header.

any ideas?

<Fluent:Button Command="{Binding ProgramSpeedCommand}" Header="{Binding ApplicationRobotControl.Robot.ProgramSpeed, FallbackValue=0}" Icon="pack://application:,,,/KUKA.RGI v3;component/Icons/hand.ico" LargeIcon="pack://application:,,,/KUKA.RGI v3;component/Icons/hand.ico"> <Fluent:Button.ToolTip> <Fluent:ScreenTip Title="Program Speed" Width="250" DisableReason="This control is disabled to show 'disable reason' section" HelpTopic="Help for Orange ScreenTip" Image="pack://application:,,,/KUKA.RGI v3;component/Images/hand.png" Text="This control is disabled and has fixed width 250px" /> </Fluent:Button.ToolTip> </Fluent:Button>

[batzen]

Could you remove the FallbackValue and try it again?
I have seen very strange behavior of bindings in combination with fallback values recently.

[PJonHar]

I have tried removing the FallbackValue but the value doesnt show on the ribbon button.

[batzen]

Could you share a repro?

[PJonHar]

Sure, see attached.

FluentRepro.zip

[batzen]

That's quite strange.
Most controls in Fluent.Ribbon use a TemplateBinding for the header, which does not seem to work when the bound value is not a string.
It works again if using a Binding with a relative source...

[PJonHar]

If possible could you show me a workaround please?

[batzen]

A workaround for you would be:

        public string ProgramSpeedString { get => programSpeed.ToString(); }
        public int ProgramSpeed { get => programSpeed; set { programSpeed = value; NotifyPropertyChanged(nameof(ProgramSpeed)); NotifyPropertyChanged(nameof(ProgramSpeedString)); } }

And then bind to ProgramSpeedString instead of ProgramSpeed.

[PJonHar]

Thanks.
I ended up using a converter to return the ToString() of an object.