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CHotKeyCtrl Class

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The latest version of this topic can be found at CHotKeyCtrl Class.

Provides the functionality of the Windows common hot key control.

Syntax

class CHotKeyCtrl : public CWnd

Members

Public Constructors

Name Description
CHotKeyCtrl::CHotKeyCtrl Constructs a CHotKeyCtrl object.

Public Methods

Name Description
CHotKeyCtrl::Create Creates a hot key control and attaches it to a CHotKeyCtrl object.
CHotKeyCtrl::CreateEx Creates a hot key control with the specified Windows extended styles and attaches it to a CHotKeyCtrl object.
CHotKeyCtrl::GetHotKey Retrieves the virtual key code and modifier flags of a hot key from a hot key control.
CHotKeyCtrl::GetHotKeyName Retrieves the key name, in the local character set, assigned to a hot key.
CHotKeyCtrl::GetKeyName Retrieves the key name, in the local character set, assigned to the specified virtual key code.
CHotKeyCtrl::SetHotKey Sets the hot key combination for a hot key control.
CHotKeyCtrl::SetRules Defines the invalid combinations and the default modifier combination for a hot key control.

Remarks

A "hot key control" is a window that enables the user to create a hot key. A "hot key" is a key combination that the user can press to perform an action quickly. (For example, a user can create a hot key that activates a given window and brings it to the top of the Z order.) The hot key control displays the user's choices and ensures that the user selects a valid key combination.

This control (and therefore the CHotKeyCtrl class) is available only to programs running under Windows 95/98 and Windows NT version 3.51 and later.

When the user has chosen a key combination, the application can retrieve the specified key combination from the control and use the WM_SETHOTKEY message to set up the hot key in the system. Whenever the user presses the hot key thereafter, from any part of the system, the window specified in the WM_SETHOTKEY message receives a WM_SYSCOMMAND message specifying SC_HOTKEY. This message activates the window that receives it. The hot key remains valid until the application that called WM_SETHOTKEY exits.

This mechanism is different from the hot key support that depends on the WM_HOTKEY message and the Windows RegisterHotKey and UnregisterHotKey functions.

For more information on using CHotKeyCtrl, see Controls and Using CHotKeyCtrl.

Inheritance Hierarchy

CObject

CCmdTarget

CWnd

CHotKeyCtrl

Requirements

Header: afxcmn.h

CHotKeyCtrl::CHotKeyCtrl

Constructs a CHotKeyCtrl object.

CHotKeyCtrl();

CHotKeyCtrl::Create

Creates a hot key control and attaches it to a CHotKeyCtrl object.

virtual BOOL Create(
    DWORD dwStyle,  
    const RECT& rect,  
    CWnd* pParentWnd,  
    UINT nID);

Parameters

dwStyle
Specifies the hot key control's style. Apply any combination of control styles. See Common Control Styles in the Windows SDK for more information.

rect
Specifies the hot key control's size and position. It can be either a CRect object or a RECT structure.

pParentWnd
Specifies the hot key control's parent window, usually a CDialog. It must not be NULL.

nID
Specifies the hot key control's ID.

Return Value

Nonzero, if initialization was successful; otherwise 0.

Remarks

You construct a CHotKeyCtrl object in two steps. First, call the constructor and then call Create, which creates the hot key control and attaches it to the CHotKeyCtrl object.

If you want to use extended windows styles with your control, call CreateEx instead of Create.

CHotKeyCtrl::CreateEx

Call this function to create a control (a child window) and associate it with the CHotKeyCtrl object.

virtual BOOL CreateEx(
    DWORD dwExStyle,  
    DWORD dwStyle,  
    const RECT& rect,  
    CWnd* pParentWnd,  
    UINT nID);

Parameters

dwExStyle
Specifies the extended style of the control being created. For a list of extended Windows styles, see the dwExStyle parameter for CreateWindowEx in the Windows SDK.

dwStyle
Specifies the hot key control's style. Apply any combination of control styles. For more information, see Common Control Styles in the Windows SDK.

rect
A reference to a RECT structure describing the size and position of the window to be created, in client coordinates of pParentWnd.

pParentWnd
A pointer to the window that is the control's parent.

nID
The control's child-window ID.

Return Value

Nonzero if successful; otherwise 0.

Remarks

Use CreateEx instead of Create to apply extended Windows styles, specified by the Windows extended style preface WS_EX_.

CHotKeyCtrl::GetHotKey

Retrieves the virtual key code and modifier flags of a keyboard shortcut from a hot key control.

DWORD GetHotKey() const;  
  
void GetHotKey(
    WORD& wVirtualKeyCode,  
    WORD& wModifiers) const;

Parameters

[out] wVirtualKeyCode
Virtual key code of the keyboard shortcut. For a list of standard virtual key codes, see Winuser.h.

[out] wModifiers
A bitwise combination (OR) of flags that indicate the modifier keys in the keyboard shortcut.

The modifier flags are as follows:

Flag Corresponding Key
HOTKEYF_ALT ALT key
HOTKEYF_CONTROL CTRL key
HOTKEYF_EXT Extended key
HOTKEYF_SHIFT SHIFT key

Return Value

In the first overloaded method, a DWORD that contains the virtual key code and modifier flags. The low-order byte of the low-order word contains the virtual key code, the high-order byte of the low-order word contains the modifier flags, and the high-order word is zero.

Remarks

The virtual key code and the modifier keys together define the keyboard shortcut.

CHotKeyCtrl::GetHotKeyName

Call this member function to get the localized name of the hot key.

CString GetHotKeyName() const;

Return Value

The localized name of the currently selected hot key. If there is no selected hot key, GetHotKeyName returns an empty string.

Remarks

The name that this member function returns comes from the keyboard driver. You can install a non-localized keyboard driver in a localized version of Windows, and vice versa.

CHotKeyCtrl::GetKeyName

Call this member function to get the localized name of the key assigned to a specified virtual key code.

static CString GetKeyName(
    UINT vk,  
    BOOL fExtended);

Parameters

vk
The virtual key code.

fExtended
If the virtual key code is an extended key, TRUE; otherwise FALSE.

Return Value

The localized name of the key specified by the vk parameter. If the key has no mapped name, GetKeyName returns an empty string.

Remarks

The key name that this function returns comes from the keyboard driver, so you can install a non-localized keyboard driver in a localized version of Windows, and vice versa.

Example

      CString str;

      str = CHotKeyCtrl::GetKeyName(VK_CONTROL, FALSE);

      // str is now "Ctrl", or the localized equivalent.

CHotKeyCtrl::SetHotKey

Sets the keyboard shortcut for a hot key control.

void SetHotKey(
    WORD wVirtualKeyCode,  
    WORD wModifiers);

Parameters

[in] wVirtualKeyCode
Virtual key code of the keyboard shortcut. For a list of standard virtual key codes, see Winuser.h.

[in] wModifiers
A bitwise combination (OR) of flags that indicate the modifier keys in the keyboard shortcut.

The modifier flags are as follows:

Flag Corresponding Key
HOTKEYF_ALT ALT key
HOTKEYF_CONTROL CTRL key
HOTKEYF_EXT Extended key
HOTKEYF_SHIFT SHIFT key

Remarks

The virtual key code and the modifier keys together define the keyboard shortcut.

CHotKeyCtrl::SetRules

Call this function to define the invalid combinations and the default modifier combination for a hot key control.

void SetRules(
    WORD wInvalidComb,  
    WORD wModifiers);

Parameters

wInvalidComb
Array of flags that specifies invalid key combinations. It can be a combination of the following values:

  • HKCOMB_A ALT

  • HKCOMB_C CTRL

  • HKCOMB_CA CTRL+ALT

  • HKCOMB_NONE Unmodified keys

  • HKCOMB_S SHIFT

  • HKCOMB_SA SHIFT+ALT

  • HKCOMB_SC SHIFT+CTRL

  • HKCOMB_SCA SHIFT+CTRL+ALT

wModifiers
Array of flags that specifies the key combination to use when the user enters an invalid combination. For more information on the modifier flags, see GetHotKey.

Remarks

When a user enters an invalid key combination, as defined by flags specified in wInvalidComb, the system uses the OR operator to combine the keys entered by the user with the flags specified in wModifiers. The resulting key combination is converted into a string and then displayed in the hot key control.

See Also

CWnd Class
Hierarchy Chart