Do you need to create such links from code or interactively? If from code, create an instance, set its Origin and Destination properties and add it to Diagram.Links. To let the user draw such links, create a custom behavior class and override its CreateLink method.

Ok, so it should look like this:

class MyBehavior : LinkShapesBehavior
{
	public MyBehavior(Diagram diagram) : base(diagram) {}
	protected override DiagramLink CreateLink()
	{
		return new ConnectionLink(Diagram);
	}
}

diagram.CustomBehavior = new MyBehavior(diagram);
 

Hi,

Inherit the custom class from DrawLinksBehavior instead of LinkShapesBehavior. All predefined Behavior.* members have a corresponding *Behavior class you could derive from if it's most similar to the custom functionality you need.

I hope that helps,
Stoyan

Hi,

I have a BoundDiagramLink derived from DiagramLink and I also set the diagram's Behavior to

    public class DrawBoundLinksBehavior : DrawLinksBehavior
    {
        public DrawBoundLinksBehavior(Diagram diagram) : base(diagram) { }

        protected override DiagramLink CreateLink()
        {
            return new BoundDiagramLink(Diagram);
        }
    }
 

in order to get my own BoundDiagramLinks.

I use the BoundDiagramLinks to separate the Link's data from the view and hold them in a model.
The model data is an additional Origin/DestinationID containing GuIDs that are stored in the MyNode classes Tag also.
The BoundDiagramLink also have the Origin/DestinationIndex which is already part of the DiagramLink class.
Let's only look at the OriginIndex in BoundDiagramLink:

    public class BoundDiagramLink : DiagramLink
    {
        public static readonly DependencyProperty OriginIndexProperty = DependencyProperty.Register(
            "OriginIndex",
            typeof(int),
            typeof(BoundDiagramLink),
            new PropertyMetadata(""));

        public BoundDiagramLink(Diagram parent) : base(parent) { }

        public BoundDiagramLink(Diagram parent, DiagramNode origin, DiagramNode destination)
            : base(parent, origin, destination)
        {
        }
    }
 

When the BoundDiagramLink is created in my Behavior class I run in an exception
"Default value type does not match type of property: OriginIndex".

What am I doing wrong?

Regards,
Pontius

Hi Stoyo,

thanks. Of course it works with an integer as defaultValue. I shouldn't do as much copy and paste.

I want to bind some DiagramLinks properties that describe the link.
These values are:
1. OriginIndex
2. DestinationIndex
3. OriginNodeID (that is a string that I also store inside the DiagramNodes Tag value)
4. DestinationNodeID (dito)
5. ControlPoints

If have already implemented binding for the values 1 to 4 since it is straight forward programming.
The ControlPoints are not as easy for me. Actually I do not need the first and the last ControlPoint
since these points are defined by the Nodes already.

Do you have a sample how to have data binding beween these ControlPoints and the data in my model using data binding?
Or do you have some hints how to implement that?

Thanks in advance.
Pontius

Hi Stoyo,

I did it according to your first proposal and it seems to work. Thanks.

Updating the ControlPoints is still an issue when the number of ControlPoints change.

I use the SegmentCount property to change the number of ControlPoints.
When I step through the code the SegmentCount may have a value of 5,
then I set it to the value of let's say 8. But it stays at 5 and the ControlPoints.Count is still 6.
So I run in an error when I try to access the seventh ControlPoint:
ControlPoint[6] = ...

    BoundDiagramLink link = new BoundDiagramLink(diagram, origin, destination);
    link.SetControlPoints(InnerControlPoints);
...
    public void SetControlPoints(innerControlPoints)
{
    if (innerControlPoints.Count > 0 && ControlPoints.Count > 1)
    {
        Point firstPoint = ControlPoints[0];
        Point lastPoint = ControlPoints[ControlPoints.Count - 1];

        SegmentCount = (short)(innerControlPoints.Count + 1); // without effect

        ControlPoints[0] = firstPoint;
        ControlPoints[ControlPoints.Count - 1] = lastPoint;

        for (int i = 0; i < innerControlPoints.Count; i++)
        {
            ControlPoints[i + 1] = innerControlPoints[i];
        }
    }
}
 

(Notice that my InnerControlPoints are the normal ControlPoints without the ends that are defined by the Nodes AnchorPoints already. But that's not the point here.)

How can I change the number of ControlPoints?

Regards,
Pontius

Hi Stoyo,

temporarily switching the DiagramLinks AutoRoute to false somehow leads to rerouting of the link.
However, switching the Diagram.RouteLinks to false, creating the links and switching back to true seems to work.

Regards
Pontius