gecko-dev/layout/forms/nsIComboboxControlFrame.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation. All
 * Rights Reserved.
 *
 * Contributor(s): 
 */

#ifndef nsIComboboxControlFrame_h___
#define nsIComboboxControlFrame_h___

#include "nsISupports.h"
#include "nsFont.h"

class nsFormFrame;
class nsIPresContext;
class nsString;
class nsIContent;
class nsVoidArray;
class nsCSSFrameConstructor;


// IID for the nsIComboboxControlFrame class
#define NS_ICOMBOBOXCONTROLFRAME_IID    \
{ 0x6961f791, 0xa662, 0x11d2,  \
  { 0x8d, 0xcf, 0x0, 0x60, 0x97, 0x3, 0xc1, 0x4e } }

/** 
  * nsIComboboxControlFrame is the common interface for frames of form controls. It
  * provides a uniform way of creating widgets, resizing, and painting.
  * @see nsLeafFrame and its base classes for more info
  */
class nsIComboboxControlFrame : public nsISupports {

public:
  NS_DEFINE_STATIC_IID_ACCESSOR(NS_ICOMBOBOXCONTROLFRAME_IID)

  /**
   * Indicates whether the list is dropped down
   *
   */
  NS_IMETHOD IsDroppedDown(PRBool * aDoDropDown) = 0;

  /**
   * Shows or hides the drop down
   *
   */
  NS_IMETHOD ShowDropDown(PRBool aDoDropDown) = 0;

  /**
   * Gets the Drop Down List
   *
   */
  NS_IMETHOD GetDropDown(nsIFrame** aDropDownFrame) = 0;

  /**
   * Sets the Drop Down List
   *
   */
  NS_IMETHOD SetDropDown(nsIFrame* aDropDownFrame) = 0;

  /**
   * Notifies the Combobox the List was selected
   *
   */
  NS_IMETHOD ListWasSelected(nsIPresContext* aPresContext, PRBool aForceUpdate) = 0;

  /**
   * Asks the Combobox to update the display frame
   * aDoDispatchEvent - indicates whether an event should be dispatched to the DOM
   * aForceUpdate - indicates whether the indexx and the text value should both be
   *                whether the index has changed or not.
   *
   */
  NS_IMETHOD UpdateSelection(PRBool aDoDispatchEvent, PRBool aForceUpdate, PRInt32 aNewIndex) = 0;

  /**
   * Asks the Combobox to update the display frame when the selection has
   * changed
   *
   */
  NS_IMETHOD SelectionChanged() = 0;

  /**
   *
   */
  NS_IMETHOD AbsolutelyPositionDropDown() = 0;

  /**
   *
   */
  NS_IMETHOD GetAbsoluteRect(nsRect* aRect) = 0;

  /**
   *
   */
  NS_IMETHOD MakeSureSomethingIsSelected(nsIPresContext* aPresContext) = 0;

  /**
   *
   */
  NS_IMETHOD SetFrameConstructor(nsCSSFrameConstructor *aConstructor) = 0;

  /**
   * This returns the index of the item that is currently being displayed
   * in the display area. It may differ from what the currently Selected index
   * is in in the dropdown.
   *
   * Detailed explanation: 
   * When the dropdown is dropped down via a mouse click and the user moves the mouse 
   * up and down without clicking, the currently selected item is being tracking inside 
   * the dropdown, but the combobox is not being updated. When the user selects items
   * with the arrow keys, the combobox is being updated. So when the user clicks outside
   * the dropdown and it needs to roll up it has to decide whether to keep the current 
   * selection or not. This method is used to get the current index in the combobox to
   * compare it to the current index in the dropdown to see if the combox has been updated
   * and that way it knows whether to "cancel" the the current selection residing in the 
   * dropdown. Or whether to leave the selection alone.
   */
  NS_IMETHOD GetIndexOfDisplayArea(PRInt32* aSelectedIndex) = 0;
};

#endif