Change Color Node

GoDiagram (6 and previous)
1

I’m using GoExpress 2.6.2.2.

I've a Node whose color is set when it's added to the goView.
How is it possible to change its color programmatically at runtime?
Here is my code:
node1.UserObject = colorX;
goView1.Document.InvalidateViews();
I'm sure that the UserObject Value is really modified (by debug and by saving the graph and reopening it as XML it appears correct!), but I don't see any change on the screen.
How can I obtain the refresh of the goView1?
Thanks in advance.
2

The UserObject doesn’t have anything to do with color, it’s just a property left unused by our code so that you can associate your own object with the node.



What node class are you using?

3

Ok. I’m sure I’ve written a lot of code to convert color FromArgb(…) etc… <?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

May I use the Brush property?

I've created a class TreeAppNode that extends GoBasicNode

public class TreeAppNode : GoBasicNode {

/* BEFORE

public TreeAppNode() {

this.Port.AddObserver(this);

this.LabelSpot = GoObject.Middle;

this.Editable = true;

this.Text = "";

this.Label.Editable = false;

this.Resizable = false;

this.MiddleLabelMargin = new SizeF(30, 15);

this.UserObject = NewVersion.nuovoColore; //global variable with type Color

}

*/

//NOW

public TreeAppNode(SolidBrush what_color)

{

this.Port.AddObserver(this);

this.LabelSpot = GoObject.Middle;

this.Editable = true;

this.Text = "";

this.Label.Editable = false;

this.Resizable = false;

this.MiddleLabelMargin = new SizeF(30, 15);

this.Brush = what_color;

}

Due to a business logic I’ve nodes with different colors on the canvas and it’s all OK when I add them to the goView.

But when the user makes a link between two nodes in the LinkCreated event handler I need to set the same color of the father node to the child one.

What’s the error in the code I append here?

private void goViewGraph_LinkCreated(object sender, GoSelectionEventArgs e)

{

TreeAppNode nFather = (TreeAppNode)((GoLink)e.GoObject).FromNode;

TreeAppNode nSon = (TreeAppNode)((GoLink)e.GoObject).ToNode;

Brush colFather = nFather.Brush;

nSon.Brush = colFather;

goViewGraph.Document.InvalidateViews();

goViewGraph.UpdateView();

}

I can’t see any change on the screen.

4

Yes, the Brush property is the right thing to use.



You shouldn’t have to call InvalidateViews or UpdateView. Go objects are smart enough to repaint themselves when a property changes.



And one important rule… you can’t change a Pen or a Brush after it has been set into a GoObject. You must create a new pen/brush.

5

Hi Jake, sorry to come back this issue.

How to create a new pen/brush? I get stuck with several nodes, if I change the color of a node, the other nodes’ colors are also changed, even the original node on palette :(