bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/widgets/TreeItem.java

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;

 
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;

/**
 * Instances of this class represent a selectable user interface object
 * that represents a hierarchy of tree items in a tree widget.
 * 
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>(none)</dd>
 * <dt><b>Events:</b></dt>
 * <dd>(none)</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 */

public class TreeItem extends Item {
	/**
	 * the handle to the OS resource 
	 * (Warning: This field is platform dependent)
	 */	
	public int handle;
	
	Tree parent;
	int background, foreground;
	int font;
	
/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Tree</code> or a <code>TreeItem</code>)
 * and a style value describing its behavior and appearance.
 * The item is added to the end of the items maintained by its parent.
 * <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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TreeItem (Tree parent, int style) {
	super (parent, style);
	this.parent = parent;
	parent.createItem (this, 0, OS.TVI_LAST);
}

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Tree</code> or a <code>TreeItem</code>),
 * a style value describing its behavior and appearance, and the index
 * at which to place it in the items maintained by its parent.
 * <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
 * @param index the index to store the receiver in its parent
 *
 * @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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TreeItem (Tree parent, int style, int index) {
	super (parent, style);
	if (index < 0) error (SWT.ERROR_INVALID_RANGE);
	this.parent = parent;
	int hItem = OS.TVI_FIRST;
	if (index != 0) {
		int count = 1, hwnd = parent.handle;
		hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_ROOT, 0);
		while (hItem != 0 && count < index) {
			hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_NEXT, hItem);
			count++;
		}
		if (hItem == 0) error (SWT.ERROR_INVALID_RANGE);
	}
	parent.createItem (this, 0, hItem);
}

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Tree</code> or a <code>TreeItem</code>)
 * and a style value describing its behavior and appearance.
 * The item is added to the end of the items maintained by its parent.
 * <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 parentItem 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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TreeItem (TreeItem parentItem, int style) {
	super (checkNull (parentItem).parent, style);
	parent = parentItem.parent;
	int hItem = parentItem.handle;
	parent.createItem (this, hItem, OS.TVI_LAST);
}

/**
 * Constructs a new instance of this class given its parent
 * (which must be a <code>Tree</code> or a <code>TreeItem</code>),
 * a style value describing its behavior and appearance, and the index
 * at which to place it in the items maintained by its parent.
 * <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 parentItem a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 * @param index the index to store the receiver in its parent
 *
 * @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
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TreeItem (TreeItem parentItem, int style, int index) {
	super (checkNull (parentItem).parent, style);
	if (index < 0) error (SWT.ERROR_INVALID_RANGE);
	parent = parentItem.parent;
	int hItem = OS.TVI_FIRST;
	int hParent = parentItem.handle;
	if (index != 0) {
		int count = 1, hwnd = parent.handle;
		hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_CHILD, hParent);
		while (hItem != 0 && count < index) {
			hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_NEXT, hItem);
			count++;
		}
		if (hItem == 0) error (SWT.ERROR_INVALID_RANGE);
	}
	parent.createItem (this, hParent, hItem);
}

static TreeItem checkNull (TreeItem item) {
	if (item == null) SWT.error (SWT.ERROR_NULL_ARGUMENT);
	return item;
}

void _setText (String string) {
	int hwnd = parent.handle;
	int hHeap = OS.GetProcessHeap ();
	TCHAR buffer = new TCHAR (parent.getCodePage (), string, true);
	int byteCount = buffer.length () * TCHAR.sizeof;
	int pszText = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
	OS.MoveMemory (pszText, buffer, byteCount); 
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_TEXT;
	tvItem.hItem = handle;
	tvItem.pszText = pszText;
	OS.SendMessage (hwnd, OS.TVM_SETITEM, 0, tvItem);
	OS.HeapFree (hHeap, 0, pszText);
}

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

/**
 * Returns the receiver's background color.
 *
 * @return the background color
 * 
 * @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>
 * 
 * @since 2.0
 * 
 */
public Color getBackground () {
	checkWidget ();
	int pixel = (background == -1) ? parent.getBackgroundPixel() : background;
	return Color.win32_new (display, pixel);
}

/**
 * Returns a rectangle describing the receiver's size and location
 * relative to its parent.
 *
 * @return the receiver's bounding rectangle
 *
 * @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 Rectangle getBounds () {
	checkWidget ();
	int hwnd = parent.handle;
	RECT rect = new RECT ();
	rect.left = handle;
	if (OS.SendMessage (hwnd, OS.TVM_GETITEMRECT, 1, rect) == 0) {
		return new Rectangle (0, 0, 0, 0);
	}
	int width = rect.right - rect.left;
	int height = rect.bottom - rect.top;
	return new Rectangle (rect.left, rect.top, width, height);
}

/**
 * Returns <code>true</code> if the receiver is checked,
 * and false otherwise.  When the parent does not have
 * the <code>CHECK style, return false.
 * <p>
 *
 * @return the checked state
 *
 * @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 boolean getChecked () {
	checkWidget ();
	if ((parent.style & SWT.CHECK) == 0) return false;
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_STATE;
	tvItem.stateMask = OS.TVIS_STATEIMAGEMASK;
	tvItem.hItem = handle;
	int result = OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	return (result != 0) && (((tvItem.state >> 12) & 1) == 0);
}

/**
 * Returns <code>true</code> if the receiver is expanded,
 * and false otherwise.
 * <p>
 *
 * @return the expanded state
 *
 * @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 boolean getExpanded () {
	checkWidget ();
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.hItem = handle;
	tvItem.mask = OS.TVIF_STATE;
	OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	return (tvItem.state & OS.TVIS_EXPANDED) != 0;
}

/**
 * Returns the font that the receiver will use to paint textual information for this item.
 *
 * @return the receiver's font
 *
 * @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>
 *
 * @since 3.0
 */
public Font getFont () {
	checkWidget ();
	return (font == -1) ? parent.getFont () : Font.win32_new (display, font);
}

/**
 * Returns the foreground color that the receiver will use to draw.
 *
 * @return the receiver's foreground color
 *
 * @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>
 * 
 * @since 2.0
 * 
 */
public Color getForeground () {
	checkWidget ();
	int pixel = (foreground == -1) ? parent.getForegroundPixel() : foreground;
	return Color.win32_new (display, pixel);
}

/**
 * Returns <code>true</code> if the receiver is grayed,
 * and false otherwise. When the parent does not have
 * the <code>CHECK style, return false.
 * <p>
 *
 * @return the grayed state
 *
 * @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 boolean getGrayed () {
	checkWidget ();
	if ((parent.style & SWT.CHECK) == 0) return false;
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_STATE;
	tvItem.stateMask = OS.TVIS_STATEIMAGEMASK;
	tvItem.hItem = handle;
	int result = OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	return (result != 0) && ((tvItem.state >> 12) > 2);
}

/**
 * Returns the number of items contained in the receiver
 * that are direct item children of 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 ();
	int hwnd = parent.handle;
	int hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_CHILD, handle);
	if (hItem == 0) return 0;
	return parent.getItemCount (hItem);
}

/**
 * Returns an array of <code>TreeItem</code>s which are the
 * direct item children of 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 receiver's 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 TreeItem [] getItems () {
	checkWidget ();
	int hwnd = parent.handle;
	int hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_CHILD, handle);
	if (hItem == 0) return new TreeItem [0];
	return parent.getItems (hItem);
}

/**
 * Returns the receiver's parent, which must be a <code>Tree</code>.
 *
 * @return the receiver's parent
 *
 * @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 Tree getParent () {
	checkWidget ();
	return parent;
}

/**
 * Returns the receiver's parent item, which must be a
 * <code>TreeItem</code> or null when the receiver is a
 * root.
 *
 * @return the receiver's parent 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 TreeItem getParentItem () {
	checkWidget ();
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_PARAM;
	tvItem.hItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_PARENT, handle);
	if (tvItem.hItem == 0) return null;
	OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	return parent.items [tvItem.lParam];
}

void redraw () {
	if (parent.drawCount > 0) return;
	int hwnd = parent.handle;
	if (!OS.IsWindowVisible (hwnd)) return;
	RECT rect = new RECT ();
	rect.left = handle;
	if (OS.SendMessage (hwnd, OS.TVM_GETITEMRECT, 1, rect) != 0) {
		OS.InvalidateRect (hwnd, rect, true);
	}
}

void releaseChild () {
	super.releaseChild ();
	parent.destroyItem (this);
}

void releaseHandle () {
	super.releaseHandle ();
	handle = 0;
}

void releaseWidget () {
	super.releaseWidget ();
	parent = null;
}

/**
 * Sets the receiver's background color to the color specified
 * by the argument, or to the default system color for the item
 * if the argument is null.
 *
 * @param color the new color (or null)
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument 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>
 * 
 * @since 2.0
 * 
 */
public void setBackground (Color color) {
	checkWidget ();
	if (color != null && color.isDisposed ()) {
		SWT.error (SWT.ERROR_INVALID_ARGUMENT);
	}
	int pixel = -1;
	if (color != null) {
		parent.customDraw = true;
		pixel = color.handle;
	}
	if (background == pixel) return;
	background = pixel;
	redraw ();
}

/**
 * Sets the checked state of the receiver.
 * <p>
 *
 * @param checked the new checked state
 *
 * @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 setChecked (boolean checked) {
	checkWidget ();
	if ((parent.style & SWT.CHECK) == 0) return;
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_STATE;
	tvItem.stateMask = OS.TVIS_STATEIMAGEMASK;
	tvItem.hItem = handle;
	OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	int state = tvItem.state >> 12;
	if (checked) {
		if ((state & 0x1) != 0) state++;
	} else {
		if ((state & 0x1) == 0) --state;
	}
	tvItem.state = state << 12;
	OS.SendMessage (hwnd, OS.TVM_SETITEM, 0, tvItem);
}

/**
 * Sets the expanded state of the receiver.
 * <p>
 *
 * @param expanded the new expanded state
 *
 * @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 setExpanded (boolean expanded) {
	checkWidget ();
	/*
	* Feature in Windows.  When the user collapses the root
	* of a subtree that has the focus item, Windows moves
	* the selection to the root of the subtree and issues
	* a TVN_SELCHANGED to inform the programmer that the
	* seletion has changed.  When the programmer collapses
	* the same subtree using TVM_EXPAND, Windows does not
	* send the selection changed notification.  This is not
	* strictly wrong but is inconsistent.  The fix is to notice
	* that the selection has changed and issue the event.
	*/
	int hwnd = parent.handle;
	int hOldItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_CARET, 0);
	parent.ignoreExpand = true;
	OS.SendMessage (hwnd, OS.TVM_EXPAND, expanded ? OS.TVE_EXPAND : OS.TVE_COLLAPSE, handle);
	parent.ignoreExpand = false;
	int hNewItem = OS.SendMessage (hwnd, OS.TVM_GETNEXTITEM, OS.TVGN_CARET, 0);
	if (hNewItem != hOldItem) {
		Event event = new Event ();
		if (hNewItem != 0) {
			TVITEM tvItem = new TVITEM ();
			tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_PARAM;
			tvItem.hItem = hNewItem;
			if (OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem) != 0) {
				event.item = parent.items [tvItem.lParam];	
			}
			parent.hAnchor = hNewItem;
		}
		parent.sendEvent (SWT.Selection, event);
	}
}

/**
 * Sets the font that the receiver will use to paint textual information
 * for this item to the font specified by the argument, or to the default font
 * for that kind of control if the argument is null.
 *
 * @param font the new font (or null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument 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>
 * 
 * @since 3.0
 */
public void setFont (Font font){
	checkWidget ();
	if (font != null && font.isDisposed ()) {
		SWT.error (SWT.ERROR_INVALID_ARGUMENT);
	}
	int hFont = -1;
	if (font != null) {
		parent.customDraw = true;
		hFont = font.handle;
	}
	if (this.font == hFont) return;
	this.font = hFont;

	/*
	* Bug in Windows.  When the font is changed for an item,
	* the bounds for the item are not updated, causing the text
	* to be clipped.  The fix is to reset the text, causing
	* Windows to compute the new bounds using the new font.
	*/
	_setText (text);
	redraw ();
}

/**
 * Sets the receiver's foreground color to the color specified
 * by the argument, or to the default system color for the item
 * if the argument is null.
 *
 * @param color the new color (or null)
 *
 * @since 2.0
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the argument 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>
 * 
 * @since 2.0
 * 
 */
public void setForeground (Color color) {
	checkWidget ();
	if (color != null && color.isDisposed ()) {
		SWT.error (SWT.ERROR_INVALID_ARGUMENT);
	}
	int pixel = -1;
	if (color != null) {
		parent.customDraw = true;
		pixel = color.handle;
	}
	if (foreground == pixel) return;
	foreground = pixel;
	redraw ();
}

/**
 * Sets the grayed state of the receiver.
 * <p>
 *
 * @param grayed the new grayed state
 *
 * @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 setGrayed (boolean grayed) {
	checkWidget ();
	if ((parent.style & SWT.CHECK) == 0) return;
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_STATE;
	tvItem.stateMask = OS.TVIS_STATEIMAGEMASK;
	tvItem.hItem = handle;
	OS.SendMessage (hwnd, OS.TVM_GETITEM, 0, tvItem);
	int state = tvItem.state >> 12;
	if (grayed) {
		if (state <= 2) state +=2;
	} else {
		if (state > 2) state -=2;
	}
	tvItem.state = state << 12;
	OS.SendMessage (hwnd, OS.TVM_SETITEM, 0, tvItem);
}

public void setImage (Image image) {
	checkWidget ();
	/*
	* Feature in Windows.  When TVM_SETITEM is used to set
	* an image for an item, the item redraws.  This happens
	* because there is no easy way to know when a program
	* has drawn on an image that is already in the control.
	* However, an image that is an icon cannot be modified.
	* The fix is to check for the same image when the image
	* is an icon.
	*/
	if (image != null && image.type == SWT.ICON) {
		if (image.equals (this.image)) return;
	}
	super.setImage (image);
	int hwnd = parent.handle;
	TVITEM tvItem = new TVITEM ();
	tvItem.mask = OS.TVIF_HANDLE | OS.TVIF_IMAGE | OS.TVIF_SELECTEDIMAGE;
	tvItem.iImage = parent.imageIndex (image);
	tvItem.iSelectedImage = tvItem.iImage;
	tvItem.hItem = handle;
	OS.SendMessage (hwnd, OS.TVM_SETITEM, 0, tvItem);
}

public void setText (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	/*
	* Feature in Windows.  When TVM_SETITEM is used to set
	* a string for an item that is equal to the string that
	* is already there, the item redraws.  The fix is to
	* check for this case and do nothing.
	*/
	if (string.equals (text)) return;
	super.setText (string);
	_setText (string);
}

}