Prevent a DiagramLink from attaching to TableNode - Diagramming Components

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Prevent a DiagramLink from attaching to TableNode (Read 3102 times)

davidl YaBB Newbies Offline I love YaBB 1G - SP1! Posts: 15 Joined: Dec 3^rd, 2007	Prevent a DiagramLink from attaching to TableNode Dec 5^th, 2007 at 11:04pm	Print Post
	Hi All, Does anybody know if there is an easy way to prevent a link from attaching to a node? I need to prevent circular references in my diagram: meaning if a link of ShapeA is connected to ShapeB, then ShapeB can not have a link that points back to SHapeA. The code to detect the CR (circular reference) is easy enough, but I can't find a way to prevent the link from attaching when I do detect the CR. It seems like all of the link* event handlers occur a little too late - the link is already created - and even if I try e.Link.Dispose(), it is not removed from the diagram. Just wondering if anyone has implemented "custom" link prevention. Thanks for any help. -David


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Stoyo God Member Offline MindFusion support Posts: 13230 Joined: Jul 20^th, 2005	Re: Prevent a DiagramLink from attaching to TableN Reply #1 - Dec 6^th, 2007 at 6:38am	Print Post
	Hi, Here is an easy way to do that: Code private void diagram_LinkModifying(object sender, MindFusion.Diagramming.LinkValidationEventArgs e) { if (e.ChangingOrigin \|\| e.ChangingDestination) { PathFinder finder = new PathFinder(diagram, false); if (finder.FindShortestPath(e.Destination, e.Origin) != null) e.Cancel = true; } } private void diagram_LinkCreating(object sender, MindFusion.Diagramming.LinkValidationEventArgs e) { PathFinder finder = new PathFinder(diagram, false); if (finder.FindShortestPath(e.Destination, e.Origin) != null) e.Cancel = true; } This will prevent all cycles in the graph, and not only simple back references. If you wish to prevent just back-links, you could do that by examining the found path and cancel the creation/modification only when the path is of length 1. Another option is to use your own method that iterates over the OutgoingLinks collection of the destination node and looks for a link to the source node. I hope that helps, Stoyan


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davidl YaBB Newbies Offline I love YaBB 1G - SP1! Posts: 15 Joined: Dec 3^rd, 2007	Re: Prevent a DiagramLink from attaching to TableN Reply #2 - Dec 6^th, 2007 at 1:06pm	Print Post
	Stoyo, Thanks, this looks great. Is there a help document available where I could have found this information myself ? So far I have just browsed the classes and the sample to figure things out. Thanks again. -David


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Stoyo God Member Offline MindFusion support Posts: 13230 Joined: Jul 20^th, 2005	Re: Prevent a DiagramLink from attaching to TableN Reply #3 - Dec 6^th, 2007 at 4:22pm	Print Post
	You could skim through the "Programming Interface Overview" section of the help file for a higher level overview of the API. The version we are releasing now also includes a tutorial, which is pretty basic at this time, but we will extend it in the following couple of months. Stoyan


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