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Treeview key node test

Posted on 2009-05-06
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Last Modified: 2012-05-06
Hello,

I  am trying to come up with a way to test is a key is already present in a treeview before I add a node. My treeview is populated from a flat file and it is possible (though unlikely) that the file could contain duplicate records. If this is the case I would like to notify the user via a MsgBox of the duplicate. Currently the duplicates are caught by a standard error handler that traps the 35602 - key is not unique in collection message. However I would like to test for a duplicate before the new node is added (and fails).

Ex:
if treeView.Nodes("key-to-check") is nothing then
 ' add the node
else
 msgbox "Error, key-to-check already exists."
end if

Currently when I try to use this method I receive a different runtime error, something relating to the node could not be found. My node keys are not something I am willing to change as they are referenced in many places.

Is there a way I can check to see if a node with a specific key already exists without having to trap an error?

Thanks in advance for any and all suggestions.
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Question by:rite_eh
2 Comments
 
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Accepted Solution

by:
ChloesDad earned 500 total points
ID: 24320516
The easiest way is using the containskey function of a treeview

so assuming that a node was added using

dim primaryNode as treenode= New TreeNode(sometext)
                Me.TreeView1.Nodes.Add(primaryNode)

Then you can see if a node already exists using

if TreeView1.Nodes.ContainsKey(sometext) then

    msgbox "Error, key-to-check already exists."

else

  ' add the node

endif
0
 
LVL 1

Author Comment

by:rite_eh
ID: 24320788
This is a .net solution, but I am writing in both so good enough for me.

Thanks
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