bundles/org.eclipse.swt/Eclipse SWT/wpf/org/eclipse/swt/widgets/ExpandBar.java - platform/eclipse.platform.swt - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2009 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.swt.widgets;

 import org.eclipse.swt.internal.wpf.*;
 import org.eclipse.swt.*;
 import org.eclipse.swt.graphics.*;
 import org.eclipse.swt.events.*;

 /**
  * Instances of this class support the layout of selectable
  * expand bar items.
  * <p>
  * The item children that may be added to instances of this class
  * must be of type <code>ExpandItem</code>.
  * </p><p>
  * <dl>
  * <dt><b>Styles:</b></dt>
  * <dd>V_SCROLL</dd>
  * <dt><b>Events:</b></dt>
  * <dd>Expand, Collapse</dd>
  * </dl>
  * </p><p>
  * IMPORTANT: This class is <em>not</em> intended to be subclassed.
  * </p>
  *
  * @see ExpandItem
  * @see ExpandEvent
  * @see ExpandListener
  * @see ExpandAdapter
  * @see <a href="http://www.eclipse.org/swt/snippets/#expandbar">ExpandBar snippets</a>
  * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  *
  * @since 3.2
  * @noextend This class is not intended to be subclassed by clients.
  */
 public class ExpandBar extends Composite {
 	int parentingHandle;
 	Control [] children;
 	int itemCount, childCount;
 	int spacing;


 /**
  * Constructs a new instance of this class given its parent
  * and a style value describing its behavior and appearance.
  * <p>
  * The style value is either one of the style constants defined in
  * class <code>SWT</code> which is applicable to instances of this
  * class, or must be built by <em>bitwise OR</em>'ing together
  * (that is, using the <code>int</code> "|" operator) two or more
  * of those <code>SWT</code> style constants. The class description
  * lists the style constants that are applicable to the class.
  * Style bits are also inherited from superclasses.
  * </p>
  *
  * @param parent a composite control which will be the parent of the new instance (cannot be null)
  * @param style the style of control to construct
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
  *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
  * </ul>
  *
  * @see SWT#V_SCROLL
  * @see Widget#checkSubclass
  * @see Widget#getStyle
  */
 public ExpandBar (Composite parent, int style) {
 	super (parent, checkStyle (style));
 }

 Control [] _getChildren () {
 	// return children in reverse order.
 	Control[] result = new Control [childCount];
 	for (int i = 0; i < childCount; i++) {
 		result [childCount - i - 1] = children [i];
 	}
 	return result;
 }

 void addChild (Control control) {
 	super.addChild (control);
 	if (childCount == children.length) {
 		Control [] newChildren = new Control [childCount + 4];
 		System.arraycopy (children, 0, newChildren, 0, childCount);
 		children = newChildren;
 	}
 	children [childCount++] = control;
 }

 /**
  * Adds the listener to the collection of listeners who will
  * be notified when an item in the receiver is expanded or collapsed
  * by sending it one of the messages defined in the <code>ExpandListener</code>
  * interface.
  *
  * @param listener the listener which should be notified
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  *
  * @see ExpandListener
  * @see #removeExpandListener
  */
 public void addExpandListener (ExpandListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	TypedListener typedListener = new TypedListener (listener);
 	addListener (SWT.Expand, typedListener);
 	addListener (SWT.Collapse, typedListener);
 }

 protected void checkSubclass () {
 	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
 }

 static int checkStyle (int style) {
 	style &= ~SWT.H_SCROLL;
 	return style;
 }

 public Point computeSize (int wHint, int hHint, boolean changed) {
 	checkWidget ();
 	Point size = computeSize (handle, wHint, hHint, changed);
 	Rectangle trim = computeTrim (0, 0, size.x, size.y);
 	return new Point (trim.width, trim.height);
 }

 void createHandle () {
 	state |= THEME_BACKGROUND;
 	parentingHandle = OS.gcnew_Canvas ();
 	if (parentingHandle == 0) error (SWT.ERROR_NO_HANDLES);
 	scrolledHandle = OS.gcnew_ScrollViewer ();
 	if (scrolledHandle == 0) error (SWT.ERROR_NO_HANDLES);
 	handle = OS.gcnew_StackPanel ();
 	if (handle == 0) error (SWT.ERROR_NO_HANDLES);
 	int children = OS.Panel_Children (parentingHandle);
 	OS.UIElementCollection_Add (children, scrolledHandle);
 	OS.GCHandle_Free (children);
 	OS.ContentControl_Content (scrolledHandle, handle);
 }

 void createItem (ExpandItem item, int style, int index) {
 	if (!(0 <= index && index <= itemCount)) error (SWT.ERROR_INVALID_RANGE);
 	item.createWidget ();
 	int items = OS.Panel_Children (handle);
 	OS.UIElementCollection_Insert (items, index, item.topHandle ());
 	int count = OS.UIElementCollection_Count (items);
 	OS.GCHandle_Free (items);
 	if (itemCount == count) error (SWT.ERROR_ITEM_NOT_ADDED);
 	itemCount++;
 }

 void createWidget () {
 	super.createWidget ();
 	children = new Control [4];
 }

 int defaultBackground () {
 	return OS.SystemColors_ControlColor;
 }

 void deregister () {
 	super.deregister ();
 	display.removeWidget (parentingHandle);
 }

 void destroyItem (ExpandItem item) {
 	int items = OS.Panel_Children (handle);
 	OS.UIElementCollection_Remove (items, item.topHandle ());
 	int count = OS.UIElementCollection_Count (items);
 	OS.GCHandle_Free (items);
 	if (itemCount == count) error (SWT.ERROR_ITEM_NOT_REMOVED);
 	itemCount--;
 }

 void fixScrollbarVisibility () {
 	OS.ScrollViewer_SetHorizontalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Hidden);
 	if ((style & SWT.V_SCROLL) == 0) {
 		OS.ScrollViewer_SetVerticalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Hidden);
 	} else {
 		OS.ScrollViewer_SetVerticalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Auto);
 	}
 }

 Point getLocation (Control child) {
 	int topHandle = child.topHandle ();
 	int point = OS.gcnew_Point (0, 0);
 	if (point == 0) error (SWT.ERROR_NO_HANDLES);
 	int location = OS.UIElement_TranslatePoint (topHandle, point, handle);
 	int x = (int) OS.Point_X (location);
 	int y = (int) OS.Point_Y (location);
 	OS.GCHandle_Free (point);
 	OS.GCHandle_Free (location);
 	return new Point (x, y);
 }

 /**
  * Returns the item at the given, zero-relative index in the
  * receiver. Throws an exception if the index is out of range.
  *
  * @param index the index of the item to return
  * @return the item at the given index
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public ExpandItem getItem (int index) {
 	checkWidget ();
 	if (!(0 <= index && index < itemCount)) error (SWT.ERROR_INVALID_RANGE);
 	int items = OS.Panel_Children (handle);
 	ExpandItem item = getItem (items, index);
 	OS.GCHandle_Free (items);
 	return item;
 }

 ExpandItem getItem (int items, int index) {
 	int item = OS.UIElementCollection_default (items, index);
 	ExpandItem result = (ExpandItem) display.getWidget (item);
 	OS.GCHandle_Free (item);
 	return result;
 }

 /**
  * Returns the number of items contained in the receiver.
  *
  * @return the number of items
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public int getItemCount () {
 	checkWidget ();
 	return itemCount;
 }

 /**
  * Returns an array of <code>ExpandItem</code>s which are the items
  * in the receiver.
  * <p>
  * Note: This is not the actual structure used by the receiver
  * to maintain its list of items, so modifying the array will
  * not affect the receiver.
  * </p>
  *
  * @return the items in the receiver
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public ExpandItem [] getItems () {
 	checkWidget ();
 	ExpandItem [] result = new ExpandItem [itemCount];
 	int items = OS.Panel_Children (handle);
 	for (int i=0; i<itemCount; i++) {
 		result [i] = getItem (items, i);
 	}
 	OS.GCHandle_Free (items);
 	return result;
 }

 int getScrollBarHandle (int style) {
 	if ((style & SWT.H_SCROLL) != 0) return 0;
 	updateLayout (handle);
 	int template = OS.Control_Template (scrolledHandle);
 	int part = createDotNetString ("PART_VerticalScrollBar", false);
 	int scrollbar = OS.FrameworkTemplate_FindName (template, part, scrolledHandle);
 	OS.GCHandle_Free (part);
 	OS.GCHandle_Free (template);
 	return scrollbar;
 }

 /**
  * Returns the receiver's spacing.
  *
  * @return the spacing
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public int getSpacing () {
 	checkWidget ();
 	return spacing;
 }

 boolean hasItems () {
 	return true;
 }

 /**
  * Searches the receiver's list starting at the first item
  * (index 0) until an item is found that is equal to the
  * argument, and returns the index of that item. If no item
  * is found, returns -1.
  *
  * @param item the search item
  * @return the index of the item
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the item is null</li>
  *    <li>ERROR_INVALID_ARGUMENT - if the item has been disposed</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public int indexOf (ExpandItem item) {
 	checkWidget ();
 	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
 	int items = OS.Panel_Children (handle);
 	int index = OS.UIElementCollection_IndexOf (items, item.topHandle ());
 	OS.GCHandle_Free (items);
 	return index;
 }

 int parentingHandle() {
 	return parentingHandle;
 }

 void register () {
 	super.register ();
 	display.addWidget (parentingHandle, this);
 }

 void releaseChildren (boolean destroy) {
 	int items = OS.Panel_Children (handle);
 	for (int i=0; i<itemCount; i++) {
 		ExpandItem item = getItem (items, i);
 		if (item != null && !item.isDisposed ()) item.release (false);
 	}
 	OS.GCHandle_Free (items);
 	super.releaseChildren (destroy);
 }

 void releaseHandle () {
 	super.releaseHandle ();
 	if (parentingHandle != 0) OS.GCHandle_Free (parentingHandle);
 	parentingHandle = 0;
 }

 void removeChild (Control control) {
 	super.removeChild (control);
 	int index = 0;
 	while (index < childCount) {
 		if (children [index] == control) break;
 		index++;
 	}
 	if (index == childCount) return;
 	System.arraycopy (children, index+1, children, index, --childCount - index);
 	children [childCount] = null;
 }

 void removeControl (Control control) {
 	super.removeControl (control);
 	int items = OS.Panel_Children (handle);
 	for (int i=0; i<itemCount; i++) {
 		ExpandItem item = getItem (items, i);
 		if (item.control == control) {
 			item.setControl (null);
 			break;
 		}
 	}
 	OS.GCHandle_Free (items);
 }

 /**
  * Removes the listener from the collection of listeners who will
  * be notified when items in the receiver are expanded or collapsed.
  *
  * @param listener the listener which should no longer be notified
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  *
  * @see ExpandListener
  * @see #addExpandListener
  */
 public void removeExpandListener (ExpandListener listener) {
 	checkWidget ();
 	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
 	if (eventTable == null) return;
 	eventTable.unhook (SWT.Expand, listener);
 	eventTable.unhook (SWT.Collapse, listener);
 }

 void reskinChildren (int flags) {
 	if (itemCount > 0) {
 		int items = OS.Panel_Children (handle);
 		for (int i=0; i<itemCount; i++) {
 			ExpandItem item = getItem (items, i);
 			if (item != null) {
 				item.reskin(flags);
 			}
 		}
 		OS.GCHandle_Free (items);
 	}
 	super.reskinChildren (flags);
 }

 int setBounds (int x, int y, int width, int height, int flags) {
 	int result = super.setBounds (x, y, width, height, flags);
 	if ((result & RESIZED) != 0) {
 		OS.FrameworkElement_Height (scrolledHandle, height);
 		OS.FrameworkElement_Width (scrolledHandle, width);
 	}
 	return result;
 }

 /**
  * Sets the receiver's spacing. Spacing specifies the number of pixels allocated around
  * each item.
  *
  * @param spacing the spacing around each item
  *
  * @exception SWTException <ul>
  *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  * </ul>
  */
 public void setSpacing (int spacing) {
 	checkWidget ();
 	if (spacing < 0) return;
 	if (spacing == this.spacing) return;
 	this.spacing = spacing;
 	int thickness = OS.gcnew_Thickness (spacing, spacing, spacing, spacing);
 	int items = OS.Panel_Children (handle);
 	for (int i = 0; i < itemCount; i++) {
 		ExpandItem item = getItem (items, i);
 		OS.FrameworkElement_Margin (item.handle, thickness);
 	}
 	OS.GCHandle_Free (items);
 	OS.GCHandle_Free (thickness);
 }

 int topHandle () {
 	return parentingHandle;
 }
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2009 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.swt.widgets;

	import org.eclipse.swt.internal.wpf.*;
	import org.eclipse.swt.*;
	import org.eclipse.swt.graphics.*;
	import org.eclipse.swt.events.*;

	/**
	* Instances of this class support the layout of selectable
	* expand bar items.
	* <p>
	* The item children that may be added to instances of this class
	* must be of type <code>ExpandItem</code>.
	* </p><p>
	* <dl>
	* <dt><b>Styles:</b></dt>
	* <dd>V_SCROLL</dd>
	* <dt><b>Events:</b></dt>
	* <dd>Expand, Collapse</dd>
	* </dl>
	* </p><p>
	* IMPORTANT: This class is <em>not</em> intended to be subclassed.
	* </p>
	*
	* @see ExpandItem
	* @see ExpandEvent
	* @see ExpandListener
	* @see ExpandAdapter
	* @see <a href="http://www.eclipse.org/swt/snippets/#expandbar">ExpandBar snippets</a>
	* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
	* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
	*
	* @since 3.2
	* @noextend This class is not intended to be subclassed by clients.
	*/
	public class ExpandBar extends Composite {
	int parentingHandle;
	Control [] children;
	int itemCount, childCount;
	int spacing;


	/**
	* Constructs a new instance of this class given its parent
	* and a style value describing its behavior and appearance.
	* <p>
	* The style value is either one of the style constants defined in
	* class <code>SWT</code> which is applicable to instances of this
	* class, or must be built by <em>bitwise OR</em>'ing together
	* (that is, using the <code>int</code> "\|" operator) two or more
	* of those <code>SWT</code> style constants. The class description
	* lists the style constants that are applicable to the class.
	* Style bits are also inherited from superclasses.
	* </p>
	*
	* @param parent a composite control which will be the parent of the new instance (cannot be null)
	* @param style the style of control to construct
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
	* <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
	* </ul>
	*
	* @see SWT#V_SCROLL
	* @see Widget#checkSubclass
	* @see Widget#getStyle
	*/
	public ExpandBar (Composite parent, int style) {
	super (parent, checkStyle (style));
	}

	Control [] _getChildren () {
	// return children in reverse order.
	Control[] result = new Control [childCount];
	for (int i = 0; i < childCount; i++) {
	result [childCount - i - 1] = children [i];
	}
	return result;
	}

	void addChild (Control control) {
	super.addChild (control);
	if (childCount == children.length) {
	Control [] newChildren = new Control [childCount + 4];
	System.arraycopy (children, 0, newChildren, 0, childCount);
	children = newChildren;
	}
	children [childCount++] = control;
	}

	/**
	* Adds the listener to the collection of listeners who will
	* be notified when an item in the receiver is expanded or collapsed
	* by sending it one of the messages defined in the <code>ExpandListener</code>
	* interface.
	*
	* @param listener the listener which should be notified
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*
	* @see ExpandListener
	* @see #removeExpandListener
	*/
	public void addExpandListener (ExpandListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Expand, typedListener);
	addListener (SWT.Collapse, typedListener);
	}

	protected void checkSubclass () {
	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
	}

	static int checkStyle (int style) {
	style &= ~SWT.H_SCROLL;
	return style;
	}

	public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget ();
	Point size = computeSize (handle, wHint, hHint, changed);
	Rectangle trim = computeTrim (0, 0, size.x, size.y);
	return new Point (trim.width, trim.height);
	}

	void createHandle () {
	state \|= THEME_BACKGROUND;
	parentingHandle = OS.gcnew_Canvas ();
	if (parentingHandle == 0) error (SWT.ERROR_NO_HANDLES);
	scrolledHandle = OS.gcnew_ScrollViewer ();
	if (scrolledHandle == 0) error (SWT.ERROR_NO_HANDLES);
	handle = OS.gcnew_StackPanel ();
	if (handle == 0) error (SWT.ERROR_NO_HANDLES);
	int children = OS.Panel_Children (parentingHandle);
	OS.UIElementCollection_Add (children, scrolledHandle);
	OS.GCHandle_Free (children);
	OS.ContentControl_Content (scrolledHandle, handle);
	}

	void createItem (ExpandItem item, int style, int index) {
	if (!(0 <= index && index <= itemCount)) error (SWT.ERROR_INVALID_RANGE);
	item.createWidget ();
	int items = OS.Panel_Children (handle);
	OS.UIElementCollection_Insert (items, index, item.topHandle ());
	int count = OS.UIElementCollection_Count (items);
	OS.GCHandle_Free (items);
	if (itemCount == count) error (SWT.ERROR_ITEM_NOT_ADDED);
	itemCount++;
	}

	void createWidget () {
	super.createWidget ();
	children = new Control [4];
	}

	int defaultBackground () {
	return OS.SystemColors_ControlColor;
	}

	void deregister () {
	super.deregister ();
	display.removeWidget (parentingHandle);
	}

	void destroyItem (ExpandItem item) {
	int items = OS.Panel_Children (handle);
	OS.UIElementCollection_Remove (items, item.topHandle ());
	int count = OS.UIElementCollection_Count (items);
	OS.GCHandle_Free (items);
	if (itemCount == count) error (SWT.ERROR_ITEM_NOT_REMOVED);
	itemCount--;
	}

	void fixScrollbarVisibility () {
	OS.ScrollViewer_SetHorizontalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Hidden);
	if ((style & SWT.V_SCROLL) == 0) {
	OS.ScrollViewer_SetVerticalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Hidden);
	} else {
	OS.ScrollViewer_SetVerticalScrollBarVisibility (scrolledHandle, OS.ScrollBarVisibility_Auto);
	}
	}

	Point getLocation (Control child) {
	int topHandle = child.topHandle ();
	int point = OS.gcnew_Point (0, 0);
	if (point == 0) error (SWT.ERROR_NO_HANDLES);
	int location = OS.UIElement_TranslatePoint (topHandle, point, handle);
	int x = (int) OS.Point_X (location);
	int y = (int) OS.Point_Y (location);
	OS.GCHandle_Free (point);
	OS.GCHandle_Free (location);
	return new Point (x, y);
	}

	/**
	* Returns the item at the given, zero-relative index in the
	* receiver. Throws an exception if the index is out of range.
	*
	* @param index the index of the item to return
	* @return the item at the given index
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public ExpandItem getItem (int index) {
	checkWidget ();
	if (!(0 <= index && index < itemCount)) error (SWT.ERROR_INVALID_RANGE);
	int items = OS.Panel_Children (handle);
	ExpandItem item = getItem (items, index);
	OS.GCHandle_Free (items);
	return item;
	}

	ExpandItem getItem (int items, int index) {
	int item = OS.UIElementCollection_default (items, index);
	ExpandItem result = (ExpandItem) display.getWidget (item);
	OS.GCHandle_Free (item);
	return result;
	}

	/**
	* Returns the number of items contained in the receiver.
	*
	* @return the number of items
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int getItemCount () {
	checkWidget ();
	return itemCount;
	}

	/**
	* Returns an array of <code>ExpandItem</code>s which are the items
	* in the receiver.
	* <p>
	* Note: This is not the actual structure used by the receiver
	* to maintain its list of items, so modifying the array will
	* not affect the receiver.
	* </p>
	*
	* @return the items in the receiver
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public ExpandItem [] getItems () {
	checkWidget ();
	ExpandItem [] result = new ExpandItem [itemCount];
	int items = OS.Panel_Children (handle);
	for (int i=0; i<itemCount; i++) {
	result [i] = getItem (items, i);
	}
	OS.GCHandle_Free (items);
	return result;
	}

	int getScrollBarHandle (int style) {
	if ((style & SWT.H_SCROLL) != 0) return 0;
	updateLayout (handle);
	int template = OS.Control_Template (scrolledHandle);
	int part = createDotNetString ("PART_VerticalScrollBar", false);
	int scrollbar = OS.FrameworkTemplate_FindName (template, part, scrolledHandle);
	OS.GCHandle_Free (part);
	OS.GCHandle_Free (template);
	return scrollbar;
	}

	/**
	* Returns the receiver's spacing.
	*
	* @return the spacing
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int getSpacing () {
	checkWidget ();
	return spacing;
	}

	boolean hasItems () {
	return true;
	}

	/**
	* Searches the receiver's list starting at the first item
	* (index 0) until an item is found that is equal to the
	* argument, and returns the index of that item. If no item
	* is found, returns -1.
	*
	* @param item the search item
	* @return the index of the item
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the item is null</li>
	* <li>ERROR_INVALID_ARGUMENT - if the item has been disposed</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int indexOf (ExpandItem item) {
	checkWidget ();
	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
	int items = OS.Panel_Children (handle);
	int index = OS.UIElementCollection_IndexOf (items, item.topHandle ());
	OS.GCHandle_Free (items);
	return index;
	}

	int parentingHandle() {
	return parentingHandle;
	}

	void register () {
	super.register ();
	display.addWidget (parentingHandle, this);
	}

	void releaseChildren (boolean destroy) {
	int items = OS.Panel_Children (handle);
	for (int i=0; i<itemCount; i++) {
	ExpandItem item = getItem (items, i);
	if (item != null && !item.isDisposed ()) item.release (false);
	}
	OS.GCHandle_Free (items);
	super.releaseChildren (destroy);
	}

	void releaseHandle () {
	super.releaseHandle ();
	if (parentingHandle != 0) OS.GCHandle_Free (parentingHandle);
	parentingHandle = 0;
	}

	void removeChild (Control control) {
	super.removeChild (control);
	int index = 0;
	while (index < childCount) {
	if (children [index] == control) break;
	index++;
	}
	if (index == childCount) return;
	System.arraycopy (children, index+1, children, index, --childCount - index);
	children [childCount] = null;
	}

	void removeControl (Control control) {
	super.removeControl (control);
	int items = OS.Panel_Children (handle);
	for (int i=0; i<itemCount; i++) {
	ExpandItem item = getItem (items, i);
	if (item.control == control) {
	item.setControl (null);
	break;
	}
	}
	OS.GCHandle_Free (items);
	}

	/**
	* Removes the listener from the collection of listeners who will
	* be notified when items in the receiver are expanded or collapsed.
	*
	* @param listener the listener which should no longer be notified
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*
	* @see ExpandListener
	* @see #addExpandListener
	*/
	public void removeExpandListener (ExpandListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Expand, listener);
	eventTable.unhook (SWT.Collapse, listener);
	}

	void reskinChildren (int flags) {
	if (itemCount > 0) {
	int items = OS.Panel_Children (handle);
	for (int i=0; i<itemCount; i++) {
	ExpandItem item = getItem (items, i);
	if (item != null) {
	item.reskin(flags);
	}
	}
	OS.GCHandle_Free (items);
	}
	super.reskinChildren (flags);
	}

	int setBounds (int x, int y, int width, int height, int flags) {
	int result = super.setBounds (x, y, width, height, flags);
	if ((result & RESIZED) != 0) {
	OS.FrameworkElement_Height (scrolledHandle, height);
	OS.FrameworkElement_Width (scrolledHandle, width);
	}
	return result;
	}

	/**
	* Sets the receiver's spacing. Spacing specifies the number of pixels allocated around
	* each item.
	*
	* @param spacing the spacing around each item
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setSpacing (int spacing) {
	checkWidget ();
	if (spacing < 0) return;
	if (spacing == this.spacing) return;
	this.spacing = spacing;
	int thickness = OS.gcnew_Thickness (spacing, spacing, spacing, spacing);
	int items = OS.Panel_Children (handle);
	for (int i = 0; i < itemCount; i++) {
	ExpandItem item = getItem (items, i);
	OS.FrameworkElement_Margin (item.handle, thickness);
	}
	OS.GCHandle_Free (items);
	OS.GCHandle_Free (thickness);
	}

	int topHandle () {
	return parentingHandle;
	}
	}