Binding to Button in WPF DataGrid does not update

Question

I have a DataGrid in my WPF app with columns that hold boolean values. I want to mirror the DataGridCheckBoxColumn but I want to change the checkbox into a colored textbox. So for a true value it will show a green "Pass" and for false a red "Fail". I've tried setting DataGridCheckBoxColumn.ElementStyle and also a DataGridTemplateColumn with a button inside but the bindings don't update. They are set fine when it's loaded but not when the item is updated. The data grid holds a collection of TestPointAttempts.

Here's my code for the template column with a button inside of it.

<DataGridTemplateColumn Header="Talk Out"  >
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <Button Content="{Binding TalkOut, Converter={StaticResource BoolToPassFailConverter}, Mode=TwoWay}" 
                                    Foreground="{Binding TalkOut, Converter={StaticResource BoolToGreenRedConverter}, Mode=TwoWay}" 
                                    Style="{StaticResource TestResultButtonStyle}" 
                                    Click="TalkOutButton_Click"/>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

I'm able to get the click event working and update the "TalkOut" value in code, but the button Text and Foreground do not update. In my viewmodel I have code to update the items. I grab the selected cell as a TestPointAttempt and pass it to the viewmodel to update. Here's my viewmodel code:

public void ToggleTestResult(TestPointAttempt tpa, bool inOutSwitch)
    {
        if (inOutSwitch)
        {
            tpa.TalkIn = !tpa.TalkIn;
            RaisePropertyChanged(() => tpa.TalkIn);
        }
        else
        {
            tpa.TalkOut = !tpa.TalkOut;
            RaisePropertyChanged(() => tpa.TalkOut);
        }
    }

And here's my testPointAttempt model:

 public class TestPointAttempt
{
    public string Id { get; set; }

    public int TestAttemptNumber { get; set; }

    public bool? TalkIn { get; set; }
    public bool? TalkOut { get; set; }
    ...
}

How do I get the cell to update on a change?

Answer 1

the TestPointAttempt needs to implement INotifyPropertyChanged and the setter needs to trigger the propertyChanged event.

Another alternative is to use Fody for that.