Object reference not set to an instance of an object

[DanielBarnes1]

I am creating a class which Inherits the TreeNode class and I am creating my own key property within the class.

I can loop round the collection and display MyNewKey for each entry in the collection as below

oSearch = My TreeNode Collection
oChild = Is My Class Containing the Ney TreeNode Key

For Each oChild In oSearch
msgbox oChild.MyNewKey
Next

The problem I am having is I wish to just get data from MyNewKey with the Node which has been selected and not have it in a loop

I have tried several ways to do this and keep getting the error message Object reference not set to an instance of an object.

I reliase that my problem is my new class has to be linked to the treeview control.

Does anybody have any ideas.

Thanks

Daniel

[nemaroller]

Well you definitely started out correct by Inheriting TreeNode class, and adding your property.

I guess what I don't properly understand is how you are adding them to a treenode control.

Anyway, because treenode control has a selectednode property, if implemented properly you should be able to grab the selectednode, and use your custom key property.

Dim selectedNode As myTreeView1.SelectedNode
MessageBox.Show(selectedNode.MyNewKey)

[DanielBarnes1]

This does not seem to work. It doesn't let me declare SelectedNode as the TreeView control.

I am using the following line to declasre SelectedNode

Dim SelectedNodeAs treeview1.selectedmode

Do you have any other Ideas Or am I just be stuppid

Also I use the following line of code to add the Node and my Key

oNode.Nodes.Add(New MyTreeNodeClass(sString, sKey)

[alextyx]

I have never used the controls you are discussing about, anyway the kind of error you obtained, in many cases is due to the fact that in a declaration you didn't put "new", that means the object is not created. For example

Dim oForm as FrmIDesignedYesterday

will give you the same problem. If you write:

Dim oForm as NEW FrmIDesignedYesterday

It works!

Obviously everyword I have written will result absolutely out of the problem, I think.



Good job