Change image source dynamically (StaticResource)

Question

I want to change the image displayed in a grid depending on a certain condition (e.g. an enum value). The problem is that the image sources are DrawingImage (provided from xaml file).

<Grid>
        <Image Source="{StaticResource BodyDrawingImage}"></Image>
</Grid>

I want that BodyDrawingImage (which is a key for DrawingImage) to be selected at run-time (by a binding i guess) from a list of DrawingImage keys but I can't figure out how to do this.

Answer 1

The way I've handled this is using a value converter class, with a property corresponding to each element of the Enum type.

public class perDialogIconConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (!(value is perDialogIcon))
        {
            return null;
        }

        switch ((perDialogIcon) value)
        {
            case perDialogIcon.Asterisk:
                return AsteriskIcon;
            case perDialogIcon.Error:
                return ErrorIcon;
            case perDialogIcon.Exclamation:
                return ExclamationIcon;
            case perDialogIcon.Hand:
                return HandIcon;
            case perDialogIcon.Information:
                return InformationIcon;
            case perDialogIcon.Question:
                return QuestionIcon;
            case perDialogIcon.Stop:
                return StopIcon;
            case perDialogIcon.Warning:
                return WarningIcon;
            default:
                return null;
        }
    }

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

    public UIElement AsteriskIcon { get; set; }
    public UIElement ErrorIcon { get; set; }
    public UIElement ExclamationIcon { get; set; }
    public UIElement HandIcon { get; set; }
    public UIElement InformationIcon { get; set; }
    public UIElement QuestionIcon { get; set; }
    public UIElement StopIcon { get; set; }
    public UIElement WarningIcon { get; set; }
}

This is instantuated as a resource within the window, along with each image required

<Window.Resources>
    <Image x:Key="AsteriskIcon"
           Source="Images/Asterisk.png"
           Stretch="None" />
    <Image x:Key="ErrorIcon"
           Source="Images/Error.png"
           Stretch="None" />
    <Image x:Key="ExclamationIcon"
           Source="Images/Exclamation.png"
           Stretch="None" />
    <Image x:Key="HandIcon"
           Source="Images/Hand.png"
           Stretch="None" />
    <Image x:Key="InformationIcon"
           Source="Images/Information.png"
           Stretch="None" />
    <Image x:Key="QuestionIcon"
           Source="Images/Question.png"
           Stretch="None" />
    <Image x:Key="StopIcon"
           Source="Images/Stop.png"
           Stretch="None" />
    <Image x:Key="WarningIcon"
           Source="Images/Warning.png"
           Stretch="None" />

    <dlg:perDialogIconConverter x:Key="DialogIconConverter"
                                AsteriskIcon="{StaticResource AsteriskIcon}"
                                ErrorIcon="{StaticResource ErrorIcon}"
                                ExclamationIcon="{StaticResource ExclamationIcon}"
                                HandIcon="{StaticResource HandIcon}"
                                InformationIcon="{StaticResource InformationIcon}"
                                QuestionIcon="{StaticResource QuestionIcon}"
                                StopIcon="{StaticResource StopIcon}"
                                WarningIcon="{StaticResource WarningIcon}" />
</Window.Resources>

and then used as required as part of the binding statement - DialogIcon is an enum property on the ViewModel

<ContentPresenter Grid.Row="0"
                  Grid.Column="0"
                  VerticalAlignment="Center"
                  Content="{Binding DialogIcon, Converter={StaticResource DialogIconConverter}}" />