WPF ToolKit Datagrid refresh binding

Question

On my datagrid I've got a DataTrigger determining which colour to set the foreground (Text) to be. This value is being stored as a property of my page.

I've got this all working nicely but now I'm giving the user the functionality to set this colour themselves.

My problem is when this colour is set by the user and I update the property how do I make the datagrid now reflect this change.

Example of what I am doing below (PrivateMessages being show in different colour)

<DataTrigger Binding="{Binding Path=IsPrivate}" Value="True">                                    
    <Setter Property="Foreground" Value="{Binding ElementName=GridPage, Path=PrivateMessageColour}" />
</DataTrigger>

Any help or guidance would be most appreciated.

Thanks in advance.

Aaron McIver Aaron McIver · Accepted Answer · 2011-02-15T20:04:40

Make sure your type implements the INotifyPropertyChanged interface and you fire the change notification on the setter of your publicly exposed property which the DataTrigger is bound to when you modify the color.

EDIT: Below is an example using a TextBox and a Button to change the color...

C#:

public partial class Window1 : Window
{
    MyData _data = new MyData();

    public Window1()
    {
        InitializeComponent();

        this.DataContext = _data;
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        _data.ChangeColor();
    }
}

    public class MyData : INotifyPropertyChanged
    {
        Random _rand = new Random();
        List<String> _colors = new List<string> { "Red", "Black", "Blue" };

        public void ChangeColor()
        {
            MyColor = _colors[_rand.Next(0, 3)];
        }

        private bool _isActive = true;
        public bool IsActive
        {
            get
            {
                return _isActive;
            }
            set
            {
                _isActive = value;
                PropertyChangedEventHandler h = PropertyChanged;
                if (h != null)
                    h(this, new PropertyChangedEventArgs("IsActive"));
            }
        }


        private String _myColor = "Green";
        public String MyColor
        {
            get
            {
                return _myColor;
            }
            set
            {
                _myColor = value;
                PropertyChangedEventHandler h = PropertyChanged;
                if (h != null)
                    h(this, new PropertyChangedEventArgs("MyColor"));
            }
        }

        #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

        #endregion
    }
}

XAML:

    <Grid>
        <Button Height="25" Click="Button_Click" Content="Change Color" VerticalAlignment="Bottom" />
        <TextBox Width="200" Height="100">
            <TextBox.Style>
                <Style>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding IsActive}" Value="true">
                            <Setter Property="TextBox.Background" Value="{Binding MyColor}"/>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </TextBox.Style>
        </TextBox>
    </Grid>

WPF ToolKit Datagrid refresh binding

1 Answers