使用转换器的 WPF SVG 图像绑定

Question

I would like to change my image source from:

<Image Source="{svg:SvgImage image.svg}"/>

To something that use binding on an enum property instead:

<Resources>
    <local:MyConverter x:Key="MyConverter" />
</Resources>    

<Image Source="{svg:SvgImage Binding MyEnumProperty, Converter={StaticResource MyConverter}}" />

public enum MyEnum 
{
    Value1,
    Value2
}

public class MyConverter: IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var myValue = (MyEnum)(value);
        switch (myValue)
        {
            case MyEnum.Value1:
                return "image1.svg";
            case MyEnum.Value2:
                return "image2.svg";
            default:
                throw new NotImplementedException();
        }
    }

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

This doesn't work and I suspect that is has something to do with the svg:SvgImage and Binding MyEnumProperty being combined in the same statement.

I get the following errors:

The member "Converter" is not recognized or is not accessible.

And

The property 'Converter' was not found in type 'SvgImageExtension'.

What is the correct way to do this?

Answer 1

The expression

{svg:SvgImage Binding MyEnumProperty ...}

is not valid XAML, and because SvgImage is a markup extension, you can't bind its properties.

You may however use DataTriggers in an Image Style instead of a Binding with a Converter:

<Image>
    <Image.Style>
        <Style TargetType="Image">
            <Style.Triggers>
                <DataTrigger Binding="{Binding MyEnumProperty}" Value="Value1">
                    <Setter Property="Source" Value="{svg:SvgImage image1.svg}"/>
                </DataTrigger>
                <DataTrigger Binding="{Binding MyEnumProperty}" Value="Value2">
                    <Setter Property="Source" Value="{svg:SvgImage image2.svg}"/>
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Image.Style>
</Image>