Wpf xamlreader load xaml with custom elements

Question

I got a canvas with custom elements, similar to texboxes and shapes.

<Canvas Name="SomeCanvas" >
    <TextBox_Element   Canvas.Left="400" Canvas.Top="200" Height="50" Name="s3" Background="#57FF3ACB"  />
</Canvas>

Which im saving to a file with:

SerializeToXML(filename, SomeCanvas);

Later I´m trying to load that file and convert ist back to the original canvas with:

FileStream fs = File.Open(openFileDialog.FileName, FileMode.Open, FileAccess.Read);
Canvas savedCanvas = XamlReader.Load(fs) as Canvas;

The last method throws a XamlParseException:

No matching constructor found on type '...TextBox_Element'. You can use the Arguments or FactoryMethod directives to construct this type.'

Does anybody know how to restore the canvas the way it was from the file? Thanks

Answer 1

Do you have a parameterless constructor in your custom class? If not, try this:

public class TextBox_Element{

    public TextBox_Element(double x, double y){
        // code
    }
    public TextBox_Element(){
        // emptyness
    }
}

That worked for me, i hope itsolves your problem too!