Style DataTrigger Setter in Button Content is invalid

Question

<StackPanel>
    <TextBox Text="" x:Name="input"/>
    <Button Content="DataTrigger Before">
        <Button.Style>
            <Style TargetType="Button">
                <Style.Triggers>
                    <DataTrigger Binding="{Binding ElementName=input, Path=Text}" Value="1">
                        <Setter Property="Content" Value="Changed"></Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </Button.Style>
    </Button>
</StackPanel>

Style DataTrigger Setter in Button Content is invalid

Thanks

Answer 1

Your DataTrigger is not change the value of the Content property because you set it inside the Button declaration. So, once setted, it will never changed. To allow changing, you have to set the value inside the Style.

This will works (I've tried):

<StackPanel>
    <TextBox Name="input"/>
    <Button>
        <Button.Style>
            <Style TargetType="Button">
                <Setter Property="Content" Value="DataTrigger Before"></Setter>
                <Style.Triggers>
                    <DataTrigger Binding="{Binding ElementName=input, Path=Text}" Value="1">
                        <Setter Property="Content" Value="Changed"></Setter>
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </Button.Style>
    </Button>
</StackPanel>