Use the LayoutChanged event to notify your application that the control's content is changed. The LayoutChanged event is called if the control is resized, if a group is expanded or collapsed, if the control is scrolled, and so on. The Left, Top, Width and Height properties determine the location of the group's list in client coordinates.

private void LayoutChanged(object sender)
{
}

Private Sub LayoutChanged(ByVal sender As System.Object) Handles LayoutChanged
End Sub

private void LayoutChanged(object sender, EventArgs e)
{
}

void OnLayoutChanged()
{
}

void __fastcall LayoutChanged(TObject *Sender)
{
}

procedure LayoutChanged(ASender: TObject; );
begin
end;

procedure LayoutChanged(sender: System.Object; e: System.EventArgs);
begin
end;

begin event LayoutChanged()
end event LayoutChanged

Private Sub LayoutChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LayoutChanged
End Sub

Private Sub LayoutChanged()
End Sub

Private Sub LayoutChanged()
End Sub

LPARAMETERS nop

PROCEDURE OnLayoutChanged(oExplorerBar)
RETURN

<SCRIPT EVENT="LayoutChanged()" LANGUAGE="JScript">
</SCRIPT>

<SCRIPT LANGUAGE="VBScript">
Function LayoutChanged()
End Function
</SCRIPT>

Procedure OnComLayoutChanged 
	Forward Send OnComLayoutChanged 
End_Procedure

METHOD OCX_LayoutChanged() CLASS MainDialog
RETURN NIL

void onEvent_LayoutChanged()
{
}

function LayoutChanged as v ()
end function

function nativeObject_LayoutChanged()
return

C++ The following tutorial shows the steps that are required to insert an ActiveX control inside the control. Shortly, the idea is to insert child windows to the control, and to move the windows when the control fires the LayoutChanged event. The following sample shows how to add a SysTreeView32 window to the control. The following sample contains all code you need to handle ActiveX inside the control.

• Insert an ExplorerBar control ( IDC_EXPLORERBAR1 ), to the dialog (form)
• Add a variable member m_explorerBar, using the Class wizard
• Add a Tree control ( IDC_TREE1 ) to the dialog ( form )
• Add a variable member m_tree, using the Class wizard
• Locate the OnInitDialog member of the dialog
• Call the initialization functions to the OnInitDialog function like follows:

  BOOL OnInitDialog()
  {
  	....
  	initTree();
  	initExplorerBar();
  	...	
  	return TRUE;  
  }

• Implement the initTree function. For instance, the following sample adds few items to the tree control 

  void initTree()
  {
  	HTREEITEM h = m_tree.InsertItem( _T("Root") );
  	HTREEITEM hChild1 =m_tree.InsertItem( _T("Child1"), h );
  	m_tree.InsertItem( _T("SubChild1"), hChild1 );
  	m_tree.InsertItem( _T("SubChild2"), hChild1 );
  	HTREEITEM hChild2 =m_tree.InsertItem( _T("Child2"), h );
  	m_tree.Expand( h, TVE_EXPAND );
  	m_tree.Expand( hChild1, TVE_EXPAND );
  }

• Implement the initExplorerBar function like follows:

  void initExplorerBar()
  {
  	COleVariant vtMissing; V_VT( &vtMissing ) = VT_ERROR;
  	m_explorerBar.BeginUpdate();
  		// Adds a group that hosts a tree control 
  		CGroups groups = m_explorerBar.GetGroups();
  		CGroup group = groups.Add( _T("Tree inside") );
  		group.SetItemHeight( 84 );
  		group.AddItem( _T(""), vtMissing );
  		group.SetExpanded( TRUE );
  		initHost( m_tree.m_hWnd, m_explorerBar, group.GetIndex() );
  	m_explorerBar.EndUpdate();
  }

  The initExplorerBar function adds a group, and a single item to the group. The ItemHeight property of the Group object is called, to specifies the height of the item, but in our case it will specify the height of the hosted window. The initHost function changes the parent window of the host window, and holds the window's handle to the group's user data. 

• Implement the initHost function like follows:

  void initHost( HWND hWnd, CExplorerBar& explorerBar, long nGroupIndex )
  {
  	CGroup group = explorerBar.GetGroups().GetItem( COleVariant( nGroupIndex ) );
  	if ( hWnd )
  	{
  		::SetClassLong( hWnd, GCL_STYLE, CS_HREDRAW | CS_VREDRAW );
  		::SetWindowPos( explorerBar.m_hWnd, hWnd , 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE | SWP_FRAMECHANGED );
  		::SetParent( hWnd, explorerBar.m_hWnd );
  		
  		// Stores the handle to the inside window to the group's user data.
  		group.SetUserData( COleVariant( (long)hWnd ) );
  		moveHost( hWnd, explorerBar, nGroupIndex );
  	}
  }

The initHost function changes the Z order of the window, change the parent window, holds the window's handle to the group's user data, and moves the window to the new position.

• Implement the moveHost function like follows:

  void moveHost( HWND hWnd, CExplorerBar& explorerBar, long nGroupIndex )
  {
  	if ( ::IsWindow( hWnd ) )
  	{
  		CGroup group = explorerBar.GetGroups().GetItem( COleVariant( nGroupIndex ) );
  		CRect rtGroup;
  		rtGroup.left = group.GetLeft();
  		rtGroup.right = rtGroup.left + group.GetWidth();
  		rtGroup.top = group.GetTop();
  		rtGroup.bottom = rtGroup.top + group.GetHeight();
  /*
  		::SetWindowPos( hWnd, NULL, rtGroup.left, rtGroup.top, rtGroup.Width(), rtGroup.Height(), SWP_FRAMECHANGED | SWP_NOZORDER | SWP_HIDEWINDOW | SWP_NOREDRAW);
  		::SetWindowPos( hWnd, NULL, 0, 0, 0, 0, SWP_FRAMECHANGED | SWP_NOZORDER | SWP_NOSIZE | SWP_NOMOVE | ( group.GetExpanded() ? SWP_SHOWWINDOW : SWP_HIDEWINDOW ) );
  */
  		::SetWindowPos( hWnd, NULL, rtGroup.left, rtGroup.top, rtGroup.Width(), rtGroup.Height(), SWP_NOZORDER | ( group.GetExpanded() ? SWP_SHOWWINDOW : SWP_HIDEWINDOW ) );
  	}
  }

The moveHost function moves the window to the coordinates specified by Left, Top, Width and Height properties of the Group object.

• Handle the LayoutChanged event of the ExplorerBar control like follows:

  void OnLayoutChangedExplorerbar1() 
  {
  	if ( IsWindow( m_explorerBar.m_hWnd ) )
  	{
  		CGroups groups = m_explorerBar.GetGroups();
  		for ( long i = 0; i < groups.GetCount(); i++ )
  			moveHost( m_explorerBar, i );
  	}
  }

VB The following tutorial shows the steps that are required to insert an ActiveX control inside the control. Shortly, the idea is to insert child windows to the control, and to move the windows when the control fires the LayoutChanged event. The following sample shows how to add a ListBox control to the ExplorerBar control. The following sample contains all code you need to handle ActiveX inside the control.

• Insert an ExplorerBar control ( ExplorerBar1 ) to the form
• Add a ListBox control ( List1 ) to the form
• Call initialization functions in the Form_Load event like follows:

  Private Sub Form_Load()
      ...
      initList
      initExplorerBar
      ...
  End Sub

• Implement the initList function. For instance, the following sample adds few items to the ListBox control 

  Private Sub initList()
      With List1
          .AddItem "Item 1"
          .AddItem "Item 2"
          .AddItem "Item 3"
          .AddItem "Item 4"
      End With
  End Sub

• Implement the initExplorerBar function like follows:

  Private Sub initExplorerBar()
      With ExplorerBar1
          .BeginUpdate
              With .Groups.Add("List")
                  .ItemHeight = 84
                  .AddItem ""
                  initHost List1, ExplorerBar1, .Index
                  .Expanded = True
              End With
          .EndUpdate
      End With
  End Sub

  The initExplorerBar function adds a group, and a single item to the group. The ItemHeight property of the Group object is called, to specify the height of the item, but in our case it will specify the height of the hosted window. The initHost function changes the parent window of the host window, and holds the control's reference to the group's user data. 

• Implement the initHost function like follows:

  Private Sub initHost(ByVal c As Object, ByVal e As EXPLORERBARLibCtl.ExplorerBar, ByVal i As Long)
      Dim g As EXPLORERBARLibCtl.Group
      Set g = e.Groups(i)
      If Not c Is Nothing Then
          SetParent c.hwnd, e.hwnd
          g.UserData = c
          moveHost e, i
      End If
  End Sub

The initHost function change the parent window, holds the control to the group's user data, and moves the control to the new position.

• Implement the moveHost function like follows:

  Private Sub moveHost(ByVal e As EXPLORERBARLibCtl.ExplorerBar, ByVal i As Long)
  On Error Resume Next
      Dim g As EXPLORERBARLibCtl.Group
      Set g = e.Groups(i)
      Dim c As Object
      Set c = g.UserData
      If Not c Is Nothing Then
          If Not (g.Expanded) Then
              c.Visible = False
          End If
          c.Left = g.Left * Screen.TwipsPerPixelX
          c.Top = g.Top * Screen.TwipsPerPixelY
          c.Width = g.Width * Screen.TwipsPerPixelX
          c.Height = g.Height * Screen.TwipsPerPixelY
          If (g.Expanded) Then
              c.Visible = True
          End If
      End If
  End Sub

  The moveHost function moves the control to the coordinates specified by Left, Top, Width and Height properties of the Group object.

• Handle the LayoutChanged event of the ExplorerBar control like follows:

Private Sub ExplorerBar1_LayoutChanged()
    Dim g As EXPLORERBARLibCtl.Group
    For Each g In ExplorerBar1.Groups
        moveHost ExplorerBar1, g.Index
    Next
End Sub