Question

I’m relatively new to WPF and am having a hard time binding a custom class to a datagrid. While the text properties are OK (they are read-only anyway), the togglebuttons for the boolean properties are not updated in my item list, and they are also not displayed according to the values set initially. They do however respond correctly to clicks in the UI.

<Style x:Key="ToggleImageStyleBien" TargetType="ToggleButton">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate>
                <StackPanel>
                    <Image Name="img" Source="Images/transp.png"/>
                </StackPanel>
                <ControlTemplate.Triggers>
                    <Trigger Property="ToggleButton.IsChecked" Value="True">
                        <Setter TargetName="img" Property="Source" Value="Images/good.png"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Here’s the DataGrid itself:

<DataGrid AutoGenerateColumns="False" Height="Auto" Name="dataGridRevision" Width="Auto" Margin="6,6,6,0" ItemsSource="{Binding}" VerticalScrollBarVisibility="Auto" VerticalGridLinesBrush="{x:Null}">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Code" Binding="{Binding Code}" Visibility="Collapsed"/>
        <DataGridTextColumn Header="Descripción" Binding="{Binding Description}" IsReadOnly="True"/>
        <DataGridTemplateColumn Header="Bien">
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <ToggleButton Style="{StaticResource ToggleImageStyleBien}" Click="ToggleButton_Click" IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=ReviewItem.Good, Mode=TwoWay}" />
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
        </DataGridTemplateColumn>
        <DataGridTextColumn Header="Comentario" />
    </DataGrid.Columns>
</DataGrid>

This is the class I’m binding to:

public class ReviewItem
{
    public string Code { set; get; }
    public string Description { set; get; }
    public bool Good { set; get; }
    public bool Bad { set; get; }
    public string Comment { set; get; }
}

As far as I can tell, I’m not using the right Binding property in the ToggleButton, but I have tried a lot and have run out of ideas. The list properties are not changing on click, the values are not displayed according to the data.

Please help…

Thanks!

Joerg.

Changed the class to this, based on other examples found:

public class ReviewItem : INotifyPropertyChanged
{
    public string Code { set; get; }
    public string Description { set; get; }
    public bool Bad { set; get; }
    public string Comment { set; get; }

    private bool _isChecked;
    public bool Good
    {
        get { return _isChecked; }
        set
        {
            System.Diagnostics.Debug.WriteLine("Good = " + value);
            _isChecked = value;
            OnPropertyChanged("Good");
        }
    }

    private void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;
}

Answer 1

You are currently binding to UserControl.ReviewItem, which is not a valid property on a UserControl.

Try binding to DataContext.ReviewItem instead which will bind to UserControl.DataContext.ReviewItem

If you do not mean to bind to UserControl.DataContext.ReviewItem.Good, and instead want to bind to DataGrid.ReviewItems[x].Good, then you only need to bind IsChecked="{Binding Good}". This is because the default DataContext on a DataGridCell is the row’s data item, so if your collection contains a list of ReviewItems, the DataContext of the cell is already set to a ReviewItem

Also, I would highly recommend using Snoop for debugging WPF bindings. You can use it on your application to see what the DataContext is for individual UI Elements, and figure out if your bindings are correct or not.