multibinding, converters and setters : unexpected error

Question

I am trying to use a multibinding style for a button in WPF, but I get an awkward error : System.ArgumentException : ''System.Drawing.SolidBrush' n'est pas une valeur valide pour la propriété 'System.Windows.Controls.Panel.Background' d'une méthode Setter.'

Yet I am applying my setters to Button.BackgroundProperty...

here is the multibinding:

    <Button
                            Height="20"
                            Margin="2,0,2,2"
                            VerticalAlignment="Bottom"
                            Click="Btn_summary_OnClick"
                            Content="Résumé"
                            Name="btn_summary">
                            <Button.Style>
                                <MultiBinding Converter="{StaticResource StyleConverter1}">
                                    <Binding ElementName="listBoxBooks" Path="SelectedItem" />
                                    <Binding Source="{StaticResource bookManagement}" Path="SelectedTab" Mode="OneWay"/>
                                    <Binding RelativeSource="{RelativeSource Self}" Path="Name"/>
                                </MultiBinding>
                            </Button.Style>
                        </Button>

and the converter:

    public class StyleConverter1 : IMultiValueConverter
    {

        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            Style styleToApply = new Style(typeof(Button));

            Object selectedItem = values[0];
            if (selectedItem == null)
            {
                styleToApply.Setters.Add(new Setter(Button.IsEnabledProperty, false));
                return styleToApply;
            }




            styleToApply.Setters.Add(new Setter(Button.IsEnabledProperty, true));

            string selectedTab = values[1] as string;
            if (selectedTab == null)
            {
                return styleToApply;
            }


            string buttonName = values[2] as string;
            if ((selectedTab.Equals("summary") && buttonName.Equals("btn_summary"))
                || (selectedTab.Equals("end") && buttonName.Equals("btn_end"))
                || (selectedTab.Equals("amazon") && buttonName.Equals("btn_amazon"))
                )
            {
                styleToApply.Setters.Add(new Setter(Button.BackgroundProperty,Brushes.Yellow));
                styleToApply.Setters.Add(new Setter(Button.ForegroundProperty, Brushes.RoyalBlue));
            }
            else
            {
                styleToApply.Setters.Add(new Setter(Button.ForegroundProperty, Brushes.Yellow));
                styleToApply.Setters.Add(new Setter(Button.BackgroundProperty, Brushes.RoyalBlue));
            }

            return styleToApply;
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }


    }

I don't understand why VS want to apply my setters to a panel.

thank you

Answer 1

System.Drawing is the namespace for Winforms. Delete this and replace with the WPF equivalent System.Windows.Media, and you'll then use the right Brushes class.