multibind image source in xaml & wpf - wpf

Question

In my project, i have a folder called Images, where all the images iam using in my application are saved in subfolders.All the images are set to "Resource" in the buildprocess.
myproject
|__Images
|__AppImages
|__StarOn.png
|__StarOff.png
Now, if i do set my image manually like this:
<Image Source="Images\AppImages\StarOn.png" width="32" height="32"/>
the image is correctly shown in the imagebox.
i would like to set the image using a converter and a binding like this:
<Image>
<Image.Source>
<Binding Path="Number" converter="{StaticResource GetImagePathConverter}"/>
</Image.Source>
</Image>
where the number is an integer
and my converter is:
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
int questionNr=int.parse(value.ToString());
if (questionNr>100)
{
return "Images\\AppImages\\StarOn.png";
}
return "Images\\AppImages\\starOff.png";
}
but this is not changing the image ?..
what iam doing wrong ?
how can i set the image source correctly from the converter ?
thanks in advance

Answer 1

Your way of using converter is incorrect. You need to create an instance of your converter use it in your binding through StaticResource. local: is the local namespace which you need to declare in your xaml -
<Image>
<Image.Resources>
<local:GetImagePathConverter x:Key="GetImagePathConverter"/>
</Image.Resources>
<Image.Source>
<Binding Path="Number" Converter="{StaticResource GetImagePathConverter}"/>
</Image.Source>
</Image>
Also, Source property is not of type string but instead ImageSource so you need something in your converter -
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
int questionNr=int.parse(value.ToString());
if (questionNr>100)
{
return new BitmapImage(new Uri("Images\\AppImages\\StarOn.png", UriKind.Relative));
}
return new BitmapImage(new Uri("Images\\AppImages\\StarOff.png", UriKind.Relative));
}

Answer 2

See this answer.
Basically, you have to take care of the type of object that you return in your converter, you cannot return string to a property of ImageSource type.
I'm not on my dev machine, but the code is something like this:
return new BitmapImage(new Uri(the/path/to/image.png)).Source; //or '*.ImageSource', can't remember