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"Nodes" property in the TreeView control

Posted on 2004-03-22
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Last Modified: 2008-03-17
hello,
I wanted to derive a class from "TreeNodeCollection". (e.g. TreeView.Nodes Property).

Can anybody give a quick explaination as to why they would want to prevent the programmer deriving from this class?

Thanks,
D.
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Question by:dave_p_r_b
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SRigney earned 50 total points
ID: 10649335
The treenode collection is a specific child of a treeview.  It has no purpose outside of it's use in a treeview.  I would prevent it from being derived, because the programmer that derived it could then override some of the graphical functionality and not show the graphics within the node the way they need to be shown, which could then break the treeview.

If you are looking to override to only gain access to a few more properties, then I suggest creating a class that contains the text that you want to be displayed, and the additional properties that you want.   When a node is selected then you can cast it to the type of class that you added to the node in the first place and access the additional properties.
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by:dave_p_r_b
ID: 10649615
Thank you.


TreeView myTV;
myTV.Nodes.Add(myTreeNode);

I wished to add extra functionality to the TreeNodeCollection.Add() function to do some extra checks. If, according to my additional checks, it was not ok to add the node then .Add() would return without adding to the collection.

I need to compare the node that is being added to the existing nodes.

I guess I'm going about this the wrong way.


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