Simple Way to Bind an Image Class as Source to Image Control

Introduction

The Image control in WPF takes as source a URL of an image or a BitmapImage which contains a URL within. In this article, I will present a way to bind an Image class object (which does not contain an image URL) directly to an Image control source.

Using the Code

I won't talk about the conversion itself from Image to BitmapImage as we can find samples for it over the web easily (e.g. here). The idea here is to use a converter which will accept as value an Image from the binding, convert it to BitmapImage and return it to the Image control source property.

For this, we need to setup an IValueConverter that will get a value which will be of type Image and convert it to BitmapImage like this:

public class ImageToSourceConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, 
				System.Globalization.CultureInfo culture)
        {
            Image image = value as Image;
            if (image != null)
            {
                MemoryStream ms = new MemoryStream();
                image.Save(ms, image.RawFormat);
                ms.Seek(0, SeekOrigin.Begin);
                BitmapImage bi = new BitmapImage();
                bi.BeginInit();
                bi.StreamSource = ms;
                bi.EndInit();
                return bi;
            }
            return null;
        }

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

In the code behind, you will have something like this:

public Image UserImage
{
    get
        {
            return _model.UserImage;
        }
}   

And in the XAML, you will bind them directly like this:

<converters:ImageToSourceConverter x:Name="ImageToSourceConverter"/>
...
<Image source="{Binding Path=UserImage, Converter={StaticResource ImageToSourceConverter}" />   

And by that, the binding is direct between the Image and the source of the Image control.

Points of Interest

At first, I did the simple thing of converting in the viewmodel and then bind the source to an object of type BitmapImage. Once I needed it the second time in another viewmodel, it was clear I needed to do something else, and a converter was the best solution.