I found the problem. Thanks everyone!



>>>In my routine to load a treeview, I place a code on the tag which is the level and the node type code:
>>>
>>>

>>>private void LoadTree()
>>>{
>>>    TreeNode oNode;
>>>
>>>    oNode = treeView1.Nodes.Add("Customers");
>>>    oNode.Tag = "0.customers";
>>>
>>>    oNode = treeView1.Nodes.Add("Accounts");
>>>    oNode.Tag = "0.accounts";
>>>    oNode.Expand();
>>>
>>>    foreach (csItem oItem in csAppStartup.oItems.colItems)
>>>    {
>>>        oNode.Nodes.Add(oItem.sCaption);
>>>        oNode.Tag = "1." + oItem.sItemCode;
>>>    }
>>>
>>>}
>>>
>>>

>>>
>>>Then in the Mouse up I want to read the tag of the selected node to see which item the user right-clicked on:
>>>
>>>

>>>private void treeView1_MouseUp(object sender, MouseEventArgs e)
>>>{
>>>
>>>    if(e.Button == MouseButtons.Right)
>>>    {
>>>        TreeNode oNode = treeView1.SelectedNode;
>>>        string sNodeInfo = oNode.Tag.ToString();
>>>
>>>    }
>>>}
>>>

>>>
>>>On the last line I'm getting "Object reference not set to an instance of an object.".
>>>
>>>Anyone see what's wrong?
>>
>>Maybe null values in some sItemCode?
>
>When the LoadTree method finished, all Node Tags were populated with valid string values. When MouseUp executes, the Tag property for each node is null.