The Diagram.Model.ChildrenChangeComplete event can be used to determine when a new node( symbol,shape or link) has been added or removed from the diagram. The event's Diagram.NodeCollection.EventArgs event argument provides information about the node and the ensuing operation such as addition or removal.

The following code sample updates the label with information on the type of node that is added to or deleted from the Diagram:

[C#]

//Listen to the Diagram Model's ChildrenChangeComplete Event.
this.diagram1.Model.ChildrenChangeComplete+=new Syncfusion.Windows.Forms.Diagram.NodeCollection.EventHandler(Model_ChildrenChangeComplete);

//ChildrenChangeComplete Event
//Update Label2 depending on whether a Shape is added or deleted from the Diagram
private void Model_ChildrenChangeComplete(object sender, Syncfusion.Windows.Forms.Diagram.NodeCollection.EventArgs evtArgs)
{
 if (evtArgs.ChangeType.ToString() == "Insert")
 {  
  this.label2.ForeColor = Color.Blue;
  this.label2.Text = "Last Node Added: " + evtArgs.Node.Name.ToString();
 }
 else if (evtArgs.ChangeType.ToString() == "Remove")
 {  
  this.label2.ForeColor = Color.Red;
  this.label2.Text = "Last Node Removed: " + evtArgs.Node.Name.ToString();
 }
}

[VB.NET]

'Listen to the Diagram Model's ChildrenChangeComplete Event.
Me.diagram1.Model.ChildrenChangeComplete+=New Syncfusion.Windows.Forms.Diagram.NodeCollection.EventHandler(Model_ChildrenChangeComplete)
 
'ChildrenChangeComplete Event
'Update Label2 depending on whether a Shape is added or deleted from the Diagram
Private  Sub Model_ChildrenChangeComplete(ByVal sender As Object, ByVal evtArgs As Syncfusion.Windows.Forms.Diagram.NodeCollection.EventArgs)
 If evtArgs.ChangeType.ToString() = "Insert" Then
  Me.label2.ForeColor = Color.Blue
  Me.label2.Text = "Last Node Added: " + evtArgs.Node.Name.ToString()
 Else If evtArgs.ChangeType.ToString() = "Remove" Then
  Me.label2.ForeColor = Color.Red
  Me.label2.Text = "Last Node Removed: " + evtArgs.Node.Name.ToString()
 End If
End Sub