CreateCustomNodeEventArgs Class

Provides data for the TreeList.CreateCustomNode event.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v23.2.dll

NuGet Packages: DevExpress.Win.Navigation, DevExpress.Win.TreeList

Declaration

C#

public class CreateCustomNodeEventArgs :
    EventArgs

VB.NET

Public Class CreateCustomNodeEventArgs
    Inherits EventArgs

Related API Members

CreateCustomNodeEventArgs is the data class for the following events:

• TreeList.CreateCustomNode

Remarks

The TreeList.CreateCustomNode event is fired when a new node is added to a Tree List and provides the opportunity to create custom nodes (TreeListNode descendants) and add them to a Tree List. The CreateCustomNodeEventArgs class provides the CreateCustomNodeEventArgs.Node property which represents the added node. The collection of nodes to which the added node belongs and the node’s unique identifier are represented by the CreateCustomNodeEventArgs.Owner and CreateCustomNodeEventArgs.NodeID properties, respectively.

CreateCustomNodeEventArgs objects are automatically created and passed to TreeList.CreateCustomNode event handlers.

Example

The following example handles the TreeList.CreateCustomNode event to add custom nodes to the Tree List. Custom nodes are represented by the CustomTLNode class which extends the functionality of the TreeListNode class. It introduces the ChildNodesCount property which returns the total number of nodes owned by the current node.

C#

using DevExpress.XtraTreeList;
using DevExpress.XtraTreeList.Nodes;
using DevExpress.XtraTreeList.Nodes.Operations;

private void treeList1_CreateCustomNode(object sender, CreateCustomNodeEventArgs e) {
   e.Node = new CustomTLNode(e.NodeID, e.Owner);
}
// ...
public class CustomTLNode : TreeListNode {
   public CustomTLNode(int id, TreeListNodes owner) : base(id, owner) {}
   public int ChildNodesCount {
      get {
         if(this.TreeList == null) return -1;
         NodesCountOperation operation = new NodesCountOperation();
         this.TreeList.NodesIterator.DoLocalOperation(operation, this.Nodes);
         return operation.Result;
      }
   }
}
public class NodesCountOperation : TreeListOperation {
   private int result;
   public NodesCountOperation() {
      result = 0;
   }
   public override void Execute(TreeListNode node) {
      result++;
   }
   public int Result {
      get { return result; }
   }
}

VB.NET

Imports DevExpress.XtraTreeList
Imports DevExpress.XtraTreeList.Nodes
Imports DevExpress.XtraTreeList.Nodes.Operations

Private Sub TreeList1_CreateCustomNode(ByVal sender As Object, _
ByVal e As CreateCustomNodeEventArgs) Handles TreeList1.CreateCustomNode
    e.Node = New CustomTLNode(e.NodeID, e.Owner)
End Sub
' ...
Public Class CustomTLNode
    Inherits TreeListNode

    Public Sub New(ByVal id As Integer, ByVal owner As TreeListNodes)
        MyBase.New(id, owner)
    End Sub

    Public ReadOnly Property ChildNodesCount() As Integer
        Get
            If Me.TreeList Is Nothing Then
                Return -1
            End If
            Dim operation As New NodesCountOperation()
            Me.TreeList.NodesIterator.DoLocalOperation(operation, Me.Nodes)
            Return operation.Result
        End Get
    End Property
End Class

Public Class NodesCountOperation
    Inherits TreeListOperation
    Dim _result As Integer

    Public Sub New()
        _result = 0
    End Sub

    Public Overrides Sub Execute(ByVal node As TreeListNode)
        _result += 1
    End Sub

    Public ReadOnly Property Result() As Integer
        Get
            Return _result
        End Get
    End Property
End Class

Inheritance

Object

EventArgs

CreateCustomNodeEventArgs