Custom TreeNode for asp.net 2.0 treeview control

18 Jan 2006 4:48 PM

Rickey Whitworth

I want to display a treeview control that is tied to a sql database.

The child nodes will be of different types, meaning they will have different
attributes and different tables

-Root
--Service1 (select * from services) value = serviceID = 1
---Database1 (select * from databases where serviceID = ?)
---Website1 (select * from websites where serviceID = ?)

When I click on a node, I want to display attributes of that node in the
right pane. I have handled this before in a windows application by creating
a custom treeNode that has an extra field for type (service, database or
website).

Here is my custom tree node and my enumeration for type

    Public Enum NodeType
        Service
        Application
        Database
        Website
    End Enum

    Public Class CustomTreeNode
        Inherits TreeNode

        Private _ntype As NodeType

        Public Property NType() As NodeType
            Get
                Return _ntype
            End Get
            Set(ByVal value As NodeType)
                _ntype = value
            End Set
        End Property

        Public Sub New(ByVal text As String, ByVal value As String, ByVal
nType As NodeType)
            MyBase.New(text, value)
            _ntype = nType
        End Sub

        Public Sub New()
            MyBase.New()
        End Sub
    End Class

And I get an error in this function

Protected Sub TreeView1_TreeNodePopulate(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.TreeNodeEventArgs) Handles
TreeView1.TreeNodePopulate
    If e.Node.ChildNodes.Count = 0 Then
        Select Case e.Node.Depth
            Case 0
                FillAuthors(e.Node)
            Case 1
                FillTitlesForAuthors(e.Node)
            Case 2
                FillDatabase(e.Node)
        End Select
    End If
End Sub

Unable to cast object of type 'System.Web.UI.WebControls.TreeNode' to type
'CustomTreeNode'

I'm not really sure how to make this work. I can give more code samples as
needed, but I just need someone who can point me in the right direction. Is
there some other function or property of the treenode I need to override, do
I need to create a custom treeview control and override some event in it?

19 Jan 2006 2:24 AM

Steven Cheng[MSFT]

Hi Rickey,

Welcome.
As for the ASP.NET 2.0 TreeView control, we can create custom control to
derived from it , also define our custom TreeNode class.... Also,
currently I'm also discussing such similiar question with other guy in the
newsgroup, here is the web link to the thread:

#Inheriting from the TreeNode class
http://groups.google.com/group/microsoft.public.dotnet.framework.aspnet.webc
ontrols/browse_thread/thread/b0f3459b35105353/df2f38d4c2b2dc20?lnk=st&q=Inhe
riting+from+the+TreeNode+class&rnum=1&hl=en#df2f38d4c2b2dc20

Thanks,

Steven Cheng
Microsoft Online Support

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--------------------

| From: "Rickey Whitworth" <rickey@community.nospam>
| Subject: Custom TreeNode for asp.net 2.0 treeview control
| Date: Wed, 18 Jan 2006 10:48:31 -0600
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| X-Tomcat-NG: microsoft.public.dotnet.framework.aspnet.webcontrols
|
| I want to display a treeview control that is tied to a sql database.
|
| The child nodes will be of different types, meaning they will have
different
| attributes and different tables
|
| -Root
| --Service1 (select * from services) value = serviceID = 1
| ---Database1 (select * from databases where serviceID = ?)
| ---Website1 (select * from websites where serviceID = ?)
|
| When I click on a node, I want to display attributes of that node in the
| right pane. I have handled this before in a windows application by
creating
| a custom treeNode that has an extra field for type (service, database or
| website).
|
| Here is my custom tree node and my enumeration for type
|
|     Public Enum NodeType
|         Service
|         Application
|         Database
|         Website
|     End Enum
|
|     Public Class CustomTreeNode
|         Inherits TreeNode
|
|         Private _ntype As NodeType
|
|         Public Property NType() As NodeType
|             Get
|                 Return _ntype
|             End Get
|             Set(ByVal value As NodeType)
|                 _ntype = value
|             End Set
|         End Property
|
|         Public Sub New(ByVal text As String, ByVal value As String, ByVal
| nType As NodeType)
|             MyBase.New(text, value)
|             _ntype = nType
|         End Sub
|
|         Public Sub New()
|             MyBase.New()
|         End Sub
|     End Class
|
| And I get an error in this function
|
| Protected Sub TreeView1_TreeNodePopulate(ByVal sender As Object, ByVal e
As
| System.Web.UI.WebControls.TreeNodeEventArgs) Handles
| TreeView1.TreeNodePopulate
|     If e.Node.ChildNodes.Count = 0 Then
|         Select Case e.Node.Depth
|             Case 0
|                 FillAuthors(e.Node)
|             Case 1
|                 FillTitlesForAuthors(e.Node)
|             Case 2
|                 FillDatabase(e.Node)
|         End Select
|     End If
| End Sub
|
|
| Unable to cast object of type 'System.Web.UI.WebControls.TreeNode' to
type
| 'CustomTreeNode'
|
| I'm not really sure how to make this work. I can give more code samples
as
| needed, but I just need someone who can point me in the right direction.
Is
| there some other function or property of the treenode I need to override,
do
| I need to create a custom treeview control and override some event in it?
|
|
|