Question

EDIT: Note! This turned out to be a typo in my code

According to msdn , Path.Data appears to be bindable. But I am not sure how to read the Depenedency Property Information part of the msdn page. Is AffectsRender and AffectsMeasure be enough for my use?

If I use x:Name to directly assign it, the geometry appears

var curve = new GeometryGroup();
curve.Children.Add(new LineGeometry(new Point(0, 0), new Point(20, 20)));
curve.Children.Add(new LineGeometry(new Point(0, 20), new Point(20, 0)));
CurveGraph.Data = curve;

This works fine. Draws a nice “X”.

However, if I have a dependency property of type GeometryGroup in the ViewModel

var curve = new GeometryGroup();
curve.Children.Add(new LineGeometry(new Point(0, 0), new Point(20, 20)));
curve.Children.Add(new LineGeometry(new Point(0, 20), new Point(20, 0)));
GeometryData= curve;

dp :

public GeometryGroup GeometryData
    {
        get { return (GeometryGroup)GetValue(GeometryDataProperty); }
        set { SetValue(GeometryDataProperty, value); }
    }

    public static readonly DependencyProperty GeometryDataProperty =  DependencyProperty.Register("GeometryDataProperty", typeof(GeometryGroup), typeof(MiniTrendVm), new UIPropertyMetadata(new GeometryGroup()));

…then it didn’t work. Nothing happens. No “X”.

xaml :

<Path Data="{Binding GeometryData}" x:Name="CurveGraph" Stroke = "{Binding StrokeColor}" StrokeThickness = "2" Grid.RowSpan="4"/> 

Should this work? Have I fat fingered something? Or can’t the Data property be set this way? The brush was databound in both cases, so I know that the datacontext is correctly set.

Answer 1

Your DependencyProperty is registered as "GeometryDataProperty" which should be "GeometryData". Not quite sure if this actually breaks the binding. Edit: Recent tests by H.B. reveal that this probably is indeed the cause. Binding that property is possible.