CMFCMenuButton Class
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A button that displays a pop-up menu and reports on the user's menu selections.
Syntax
class CMFCMenuButton : public CMFCButton
Members
Public Constructors
| Name | Description |
|---|---|
| CMFCMenuButton::CMFCMenuButton | Constructs a CMFCMenuButton object. |
Public Methods
| Name | Description |
|---|---|
| CMFCMenuButton::PreTranslateMessage | Called by the framework to translate window messages before they are dispatched. (Overrides CMFCButton::PreTranslateMessage.) |
| CMFCMenuButton::SizeToContent | Changes the size of the button according to its text and image size. |
Data Members
| Name | Description |
|---|---|
| CMFCMenuButton::m_bOSMenu | Specifies whether to display the default system pop-up menu or to use CContextMenuManager::TrackPopupMenu. |
| CMFCMenuButton::m_bRightArrow | Specifies whether the pop-up menu will appear underneath or to the right of the button. |
| CMFCMenuButton::m_bStayPressed | Specifies whether the menu button changes its state after the user releases the button. |
| CMFCMenuButton::m_hMenu | A handle to the attached Windows menu. |
| CMFCMenuButton::m_nMenuResult | An identifier that indicates which item the user selected from the pop-up menu. |
Remarks
The CMFCMenuButton class is derived from the CMFCButton Class which is, in turn, derived from the CButton Class. Therefore, you can use CMFCMenuButton in your code the same way you would use CButton.
When you create a CMFCMenuButton, you must pass in a handle to the associated pop-up menu. Next, call the function CMFCMenuButton::SizeToContent. CMFCMenuButton::SizeToContent checks that the button size is sufficient to include an arrow that points to the location where the pop-up window will appear - namely, underneath or to the right of the button.
Example
The following example demonstrates how to set the handle of the menu attached to the button, resize the button according to its text and image size, and set the pop-up menu that is displayed by the framework. This code snippet is part of the New Controls sample.
CMFCMenuButton m_btnMenu;
// CMenu m_menu
m_btnMenu.m_hMenu = m_menu.GetSubMenu(0)->GetSafeHmenu();
m_btnMenu.SizeToContent();
// set to FALSE so that the framework calls CContextMenuManager::TrackPopupMenu
// to display its menu
m_btnMenu.m_bOSMenu = FALSE;
Inheritance Hierarchy
Requirements
Header: afxmenubutton.h
CMFCMenuButton::CMFCMenuButton
Constructs a new CMFCMenuButton object.
CMFCMenuButton();
CMFCMenuButton::m_bOSMenu
A Boolean member variable that indicates which pop-up menu the framework displays.
BOOL m_bOSMenu;
Remarks
If m_bOSMenu is TRUE, the framework calls the inherited TrackPopupMenu method for this object. Otherwise, the framework calls CContextMenuManager::TrackPopupMenu.
CMFCMenuButton::m_bRightArrow
A Boolean member variable that indicates the location of the pop-up menu.
BOOL m_bRightArrow;
Remarks
When the user presses the menu button, the application shows a pop-up menu. The framework will display the pop-up menu either under the button or to the right of the button. The button also has a small arrow that indicates where the pop-up menu will appear. If m_bRightArrow is TRUE, the framework displays the pop-up menu to the right of the button. Otherwise, it displays the pop-up menu under the button.
CMFCMenuButton::m_bStayPressed
A Boolean member variable that indicates whether the menu button appears pressed while the user makes a selection from the pop-up menu.
BOOL m_bStayPressed;
Remarks
If the m_bStayPressed member is FALSE, the menu button does not become pressed when the uses clicks the button. In this case, the framework displays only the pop-up menu.
If the m_bStayPressed member is TRUE, the menu button becomes pressed when the user clicks the button. It stays pressed until after the user closes the pop-up menu, either by making a selection or canceling.
CMFCMenuButton::m_hMenu
The handle to the attached menu.
HMENU m_hMenu;
Remarks
The framework displays the menu indicated by this member variable when the user clicks the menu button.
CMFCMenuButton::m_nMenuResult
An integer that indicates which item the user selects from the pop-up menu.
int m_nMenuResult;
Remarks
The value of this member variable is zero if the user cancels the menu without making a selection or if an error occurs.
CMFCMenuButton::PreTranslateMessage
Called by the framework to translate window messages before they are dispatched.
virtual BOOL PreTranslateMessage(MSG* pMsg);
Parameters
[in] pMsg
Points to a MSG structure that contains the message to process.
Return Value
Nonzero if the message was translated and should not be dispatched; 0 if the message was not translated and should be dispatched.
Remarks
CMFCMenuButton::SizeToContent
Changes the size of the button according to its text size and image size.
virtual CSize SizeToContent(BOOL bCalcOnly=FALSE);
Parameters
[in] bCalcOnly
A Boolean parameter that indicates whether this method resizes the button .
Return Value
A CSize object that specifies the new size for the button.
Remarks
If you call this function and bCalcOnly is TRUE, SizeToContent will calculate only the new size of the button.
The new size of the button is calculated to fit the button text, image, and arrow. The framework also adds in predefined margins of 10 pixels for the horizontal edge and 5 pixels for the vertical edge.