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Walkthrough: Putting Controls On Toolbars

  • Artigo

This topic describes how to add a toolbar button that contains a Windows control to a toolbar. In MFC, a toolbar button must be a CMFCToolBarButton Class-derived class, for example CMFCToolBarComboBoxButton Class, CMFCToolBarEditBoxButton Class, CMFCDropDownToolbarButton Class, or CMFCToolBarMenuButton Class.

Adding Controls to Toolbars

To add a control to a toolbar, follow these steps:

  1. Reserve a dummy resource ID for the button in the parent toolbar resource. For more information about how to create buttons by using the Toolbar Editor in Visual Studio, see the Toolbar Editor topic.

  2. Reserve a toolbar image (button icon) for the button in all bitmaps of the parent toolbar.

  3. In the message handler that processes the AFX_WM_RESETTOOLBAR message, do the following:

    1. Construct the button control by using a CMFCToolbarButton-derived class.

    2. Replace the dummy button with the new control by using CMFCToolBar::ReplaceButton. You can construct the button object on the stack, because ReplaceButton copies the button object and maintains the copy.

Observação

If you enabled customization in your application, you may have to reset the toolbar by using the Reset button on the Toolbars tab of the Customize dialog box to see the updated control in your application after recompiling. The toolbar state is saved in the Windows registry, and the registry information is loaded and applied after the ReplaceButton method is executed during application startup.

Toolbar Controls and Customization

The Commands tab of the Customize dialog box contains a list of commands that are available in the application. By default, the Customize dialog box processes the application menus and builds a list of standard toolbar buttons in each menu category. To retain the extended functionality that the toolbar controls provide, you must replace the standard toolbar button with the custom control in the Customize dialog box.

When you enable customization, you create the Customize dialog box in the customization handler OnViewCustomize by using the CMFCToolBarsCustomizeDialog Class class. Before you display the Customize dialog box by calling CMFCToolBarsCustomizeDialog::Create, call CMFCToolBarsCustomizeDialog::ReplaceButton to replace the standard button with the new control.

Example: Creating a Find Combo Box

This section describes how to create a Find combo box control that appears on a toolbar and contains recently-used search strings. The user can type a string in the control and then press the enter key to search a document, or press the escape key to return the focus to the main frame. This example assumes that the document is displayed in a CEditView Class-derived view.

Creating the Find Control

First, create the Find combo box control:

  1. Add the button and its commands to the application resources:

    1. In the application resources, add a new button with an ID_EDIT_FIND command ID to a toolbar in your application and to any bitmaps associated with the toolbar.

    2. Create a new menu item with the ID_EDIT_FIND command ID.

    3. Add a new string "Find the text\nFind" to the string table and assign it an ID_EDIT_FIND_COMBO command ID. This ID will be used as the command ID of the Find combo box button.

      Observação

      Because ID_EDIT_FIND is a standard command that is processed by CEditView, you are not required to implement a special handler for this command. However, you must implement a handler for the new command ID_EDIT_FIND_COMBO.

  2. Create a new class, CFindComboBox, derived from CComboBox Class.

  3. In the CFindComboBox class, override the PreTranslateMessage virtual method. This method will enable the combo box to process the WM_KEYDOWN message. If the user hits the escape key (VK_ESCAPE), return the focus to the main frame window. If the user hits the Enter key (VK_ENTER), post to the main frame window a WM_COMMAND message that contains the ID_EDIT_FIND_COMBO command ID.

  4. Create a class for the Find combo box button, derived from CMFCToolBarComboBoxButton Class. In this example, it is named CFindComboButton.

  5. The constructor of CMFCToolbarComboBoxButton takes three parameters: the command ID of the button, the button image index, and the style of the combo box. Set these parameters as follows:

    1. Pass the ID_EDIT_FIND_COMBO as the command ID.

    2. Use CCommandManager::GetCmdImage with ID_EDIT_FIND to obtain the image index.

    3. For a list of available combo box styles, see Combo-Box Styles.

  6. In the CFindComboButton class, override the CMFCToolbarComboBoxButton::CreateCombo method. Here you should create the CFindComboButton object and return a pointer to it.

  7. Use the IMPLEMENT_SERIAL macro to make the combo button persistent. The workspace manager automatically loads and saves the button's state in the Windows registry.

  8. Implement the ID_EDIT_FIND_COMBO handler in your document view. Use CMFCToolBar::GetCommandButtons with ID_EDIT_FIND_COMBO to retrieve all Find combo box buttons. There can be several copies of a button with the same command ID because of customization.

  9. In the ID_EDIT_FIND message handler OnFind, use CMFCToolBar::IsLastCommandFromButton to determine whether the find command was sent from the Find combo box button. If so, find the text and add the search string to the combo box.

Adding the Find Control to the Main Toolbar

To add the combo box button to the toolbar, follow these steps:

  1. Implement the AFX_WM_RESETTOOLBAR message handler OnToolbarReset in the main frame window.

    Observação

    The framework sends this message to the main frame window when a toolbar is initialized during application startup, or when a toolbar is reset during customization. In either case, you must replace the standard toolbar button with the custom Find combo box button.

  2. In the AFX_WM_RESETTOOLBAR handler, examine the toolbar ID, that is, the WPARAM of the AFX_WM_RESETTOOLBAR message. If the toolbar ID is equal to that of the toolbar that contains the Find combo box button, call CMFCToolBar::ReplaceButton to replace the Find button (that is, the button with the command ID ID_EDIT_FIND) with a CFindComboButton object.

    Observação

    You can construct a CFindComboBox object on the stack, because ReplaceButton copies the button object and maintains the copy.

Adding the Find Control to the Customize Dialog Box

In the customization handler OnViewCustomize, call CMFCToolBarsCustomizeDialog::ReplaceButton to replace the Find button (that is, the button with the command ID ID_EDIT_FIND) with a CFindComboButton object.

See Also

Reference

Hierarchy Chart

CMFCToolBar Class

CMFCToolBarButton Class

CMFCToolBarComboBoxButton Class

CMFCToolBarsCustomizeDialog Class

Other Resources

MFC Classes