How to: Create a Tree in Code (Unbound Mode)

• Dec 17, 2020
• 2 minutes to read

This example shows how to create a simple tree when the ASPxTreeList functions in unbound mode. New nodes are created and added to the ASPxTreeList via the ASPxTreeList.AppendNode method.

Columns can be created at design time or in code. For detailed information, see Creating Columns and Binding Them to Data Fields.

The image below shows the result:

C#

using DevExpress.Web.ASPxTreeList;

protected void Page_Load(object sender, EventArgs e) {
    CreateTree();
}

void CreateTree() {
    TreeListNode parentNode = CreateNodeCore(0, "<b>Local Folders</b>", null);
    CreateNodeCore(1, "Inbox", parentNode);
    CreateNodeCore(2, "Outbox", parentNode);
    CreateNodeCore(3, "Sent Items", parentNode);
    CreateNodeCore(4, "Deleted Items", parentNode);
    TreeListNode searchFolders = CreateNodeCore(5, "<b>Search Folders</b>", null);
    CreateNodeCore(6, "Categorized Mail", searchFolders);
    CreateNodeCore(7, "Large Mail", searchFolders);
}

TreeListNode CreateNodeCore(int key, string text, TreeListNode parentNode) {
    TreeListNode node = ASPxTreeList1.AppendNode(key, parentNode);
    node["Folder"] = text;
    return node;
}

VB.NET

Imports DevExpress.Web.ASPxTreeList

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    CreateTree()
End Sub

Sub CreateTree()
    Dim parentNode As TreeListNode = CreateNodeCore(0, "<b>Local Folders</b>", Nothing)
    CreateNodeCore(1, "Inbox", parentNode)
    CreateNodeCore(2, "Outbox", parentNode)
    CreateNodeCore(3, "Sent Items", parentNode)
    CreateNodeCore(4, "Deleted Items", parentNode)
    Dim searchFolders As TreeListNode = CreateNodeCore(5, "<b>Search Folders</b>", Nothing)
    CreateNodeCore(6, "Categorized Mail", searchFolders)
    CreateNodeCore(7, "Large Mail", searchFolders)
End Sub

Function CreateNodeCore(ByVal key As Integer, ByVal nodeText As String,_
ByVal parentNode As TreeListNode) As TreeListNode
    Dim node As TreeListNode = ASPxTreeList1.AppendNode(key, parentNode)
    node("Folder") = nodeText
    Return node
End Function

ASPX

<dxwtl:ASPxTreeList ID="ASPxTreeList1" runat="server" AutoGenerateColumns="False"
    Width="300px">
    <Columns>
        <dxwtl:TreeListTextColumn FieldName="Folder" VisibleIndex="0">
            <PropertiesTextEdit EncodeHtml="False">
            </PropertiesTextEdit>
        </dxwtl:TreeListTextColumn>
    </Columns>
</dxwtl:ASPxTreeList>