Extending the TreeNode -

9 Mar 2006 1:30 AM

Don

I've created a small test class to extend the Treenode object and am
having mixed success.

In the Treeview's 'BeforeExpand' event I've used code from the help
topic "Adding Custom Information to a TreeView or ListView Control"

I've been able to add nodes of myTreeNode type to the treeview and
verify that they really are myTreeNode type nodes but haven't been
able to get this part figured out.

Thank you for any help,

    Don

The 'CType' line produces the following error:

    'System.InvalidCastException'
    Additional information: Specified cast is not valid.

Private Sub tvSnips_BeforeExpand(REMOVED) Handles tvSnips.BeforeExpand

        Dim mynode As myTreeNode
        mynode = CType(e.Node, myTreeNode) <-------ERROR
        MessageBox.Show("Node selected is " & mynode.NodeParent)

End Sub

Public Class myTreeNode
    Inherits TreeNode
    Private mintParent As Integer

    Public Enum enumNodeType
        Dummy = -1
        Group = 0
        Leaf = 1
    End Enum

    Public nt As enumNodeType

    Public Property NodeType() As enumNodeType
        Get
            Return nt
        End Get
        Set(ByVal Value As enumNodeType)
            nt = Value
        End Set
    End Property

    Public Property NodeParent() As Integer
        Get
            Return mintParent
        End Get
        Set(ByVal Value As Integer)
            mintParent = Value
        End Set
    End Property
End Class

9 Mar 2006 7:56 AM

Nick Hounsome

Are ALL the nodes in the tree of type myTreeNode?

Show quote

"Don" <don81846@NO_CaCa.Earthlink.net> wrote in message
news:b81v02p4414sast0l7l101064qoo4qvcc9@4ax.com...
>
> I've created a small test class to extend the Treenode object and am
> having mixed success.
>
> In the Treeview's 'BeforeExpand' event I've used code from the help
> topic "Adding Custom Information to a TreeView or ListView Control"
>
> I've been able to add nodes of myTreeNode type to the treeview and
> verify that they really are myTreeNode type nodes but haven't been
> able to get this part figured out.
>
> Thank you for any help,
>
> Don
>
> The 'CType' line produces the following error:
>
> 'System.InvalidCastException'
> Additional information: Specified cast is not valid.
>
> Private Sub tvSnips_BeforeExpand(REMOVED) Handles tvSnips.BeforeExpand
>
>        Dim mynode As myTreeNode
>        mynode = CType(e.Node, myTreeNode) <-------ERROR
>        MessageBox.Show("Node selected is " & mynode.NodeParent)
>
> End Sub
>
>
> Public Class myTreeNode
>    Inherits TreeNode
>    Private mintParent As Integer
>
>    Public Enum enumNodeType
>        Dummy = -1
>        Group = 0
>        Leaf = 1
>    End Enum
>
>    Public nt As enumNodeType
>
>    Public Property NodeType() As enumNodeType
>        Get
>            Return nt
>        End Get
>        Set(ByVal Value As enumNodeType)
>            nt = Value
>        End Set
>    End Property
>
>    Public Property NodeParent() As Integer
>        Get
>            Return mintParent
>        End Get
>        Set(ByVal Value As Integer)
>            mintParent = Value
>        End Set
>    End Property
> End Class

9 Mar 2006 9:42 PM

Don

I believe they are but another smart person suggested the same thing.
I'll tripple check my code.

Thank you,

Don

On Thu, 09 Mar 2006 07:56:01 GMT, "Nick Hounsome"
<nh***@nickhounsome.me.uk> wrote:

Show quote

>Are ALL the nodes in the tree of type myTreeNode?
>
>"Don" <don81846@NO_CaCa.Earthlink.net> wrote in message
>news:b81v02p4414sast0l7l101064qoo4qvcc9@4ax.com...
>>
>> I've created a small test class to extend the Treenode object and am
>> having mixed success.
>>
>> In the Treeview's 'BeforeExpand' event I've used code from the help
>> topic "Adding Custom Information to a TreeView or ListView Control"
>>
>> I've been able to add nodes of myTreeNode type to the treeview and
>> verify that they really are myTreeNode type nodes but haven't been
>> able to get this part figured out.
>>
>> Thank you for any help,
>>
>> Don
>>

Extending the TreeNode - - -> HELP!