The WM_APPCOMMAND message notifies a window that the user generated an application command event, for example, by clicking an application command button using the mouse or typing an application command key on the keyboard.

Syntax

WM_APPCOMMAND

    WPARAM wParam
    LPARAM lParam;
    

Parameters

wParam

Handle to the window where the user clicked the button or pressed the key. This can be a child window of the window receiving the message. For more information about processing this message, see the Remarks section.

lParam

Use the following code to get the information contained in the lParam parameter.

cmd  = GET_APPCOMMAND_LPARAM(lParam);

uDevice = GET_DEVICE_LPARAM(lParam);

dwKeys = GET_KEYSTATE_LPARAM(lParam);

Where cmd indicates the application command. This parameter can be one of the following values.

APPCOMMAND_BASS_BOOST

Toggle the bass boost on and off.

APPCOMMAND_BASS_DOWN

Decrease the bass.

APPCOMMAND_BASS_UP

Increase the bass.

APPCOMMAND_BROWSER_BACKWARD

Navigate backward.

APPCOMMAND_BROWSER_FAVORITES

Open favorites.

APPCOMMAND_BROWSER_FORWARD

Navigate forward.

APPCOMMAND_BROWSER_HOME

Navigate home.

APPCOMMAND_BROWSER_REFRESH

Refresh page.

APPCOMMAND_BROWSER_SEARCH

Open search.

APPCOMMAND_BROWSER_STOP

Stop download.

APPCOMMAND_CLOSE

Windows XP: Close the window (not the application).

APPCOMMAND_COPY

Windows XP: Copy the selection.

APPCOMMAND_CORRECTION_LIST

Windows XP: Brings up the correction list when a word is incorrectly identified during speech input.

APPCOMMAND_CUT

Windows XP: Cut the selection.

APPCOMMAND_DICTATE_OR_COMMAND_CONTROL_TOGGLE

Windows XP: Toggles between two modes of speech input: dictation and command/control (giving commands to an application or accessing menus).

APPCOMMAND_FIND

Windows XP: Open the Find dialog.

APPCOMMAND_FORWARD_MAIL

Windows XP: Forward a mail message.

APPCOMMAND_HELP

Windows XP: Open the Help dialog.

APPCOMMAND_LAUNCH_APP1

Start App1.

APPCOMMAND_LAUNCH_APP2

Start App2.

APPCOMMAND_LAUNCH_MAIL

Open mail.

APPCOMMAND_MEDIA_CHANNEL_DOWN

Windows XP SP1: Decrement the channel value, for example, for a TV or radio tuner.

APPCOMMAND_MEDIA_CHANNEL_UP

Windows XP SP1: Increment the channel value, for example, for a TV or radio tuner.

APPCOMMAND_MEDIA_FASTFORWARD

Windows XP SP1: Increase the speed of stream playback. This can be implemented in many ways, for example, using a fixed speed or toggling through a series of increasing speeds.

APPCOMMAND_MEDIA_NEXTTRACK

Go to next track.

APPCOMMAND_MEDIA_PAUSE

Windows XP SP1: Pause. If already paused, take no further action. This is a direct PAUSE command that has no state. If there are discrete Play and Pause buttons, applications should take action on this command as well as APPCOMMAND_MEDIA_PLAY_PAUSE.

APPCOMMAND_MEDIA_PLAY

Windows XP SP1: Begin playing at the current position. If already paused, it will resume. This is a direct PLAY command that has no state. If there are discrete Play and Pause buttons, applications should take action on this command as well as APPCOMMAND_MEDIA_PLAY_PAUSE.

APPCOMMAND_MEDIA_PLAY_PAUSE

Play or pause playback. If there are discrete Play and Pause buttons, applications should take action on this command as well as APPCOMMAND_MEDIA_PLAY and APPCOMMAND_MEDIA_PAUSE.

APPCOMMAND_MEDIA_PREVIOUSTRACK

Go to previous track.

APPCOMMAND_MEDIA_RECORD

Windows XP SP1: Begin recording the current stream.

APPCOMMAND_MEDIA_REWIND

Windows XP SP1: Go backward in a stream at a higher rate of speed. This can be implemented in many ways, for example, using a fixed speed or toggling through a series of increasing speeds.

APPCOMMAND_MEDIA_SELECT

Go to Media Select mode.

APPCOMMAND_MEDIA_STOP

Stop playback.

APPCOMMAND_MIC_ON_OFF_TOGGLE

Windows XP: Toggle the microphone.

APPCOMMAND_MICROPHONE_VOLUME_DOWN

Windows XP: Increase microphone volume.

APPCOMMAND_MICROPHONE_VOLUME_MUTE

Windows XP: Mute the microphone.

APPCOMMAND_MICROPHONE_VOLUME_UP

Windows XP: Decrease microphone volume.

APPCOMMAND_NEW

Windows XP: Create a new window.

APPCOMMAND_OPEN

Windows XP: Open a window.

APPCOMMAND_PASTE

Windows XP: Paste

APPCOMMAND_PRINT

Windows XP: Print current document.

APPCOMMAND_REDO

Windows XP: Redo last action.

APPCOMMAND_REPLY_TO_MAIL

Windows XP: Reply to a mail message.

APPCOMMAND_SAVE

Windows XP: Save current document.

APPCOMMAND_SEND_MAIL

Windows XP: Send a mail message.

APPCOMMAND_SPELL_CHECK

Windows XP: Initiate a spell check.

APPCOMMAND_TREBLE_DOWN

Decrease the treble.

APPCOMMAND_TREBLE_UP

Increase the treble.

APPCOMMAND_UNDO

Windows XP: Undo last action.

APPCOMMAND_VOLUME_DOWN

Lower the volume.

APPCOMMAND_VOLUME_MUTE

Mute the volume.

APPCOMMAND_VOLUME_UP

Raise the volume.

Where uDevice indicates the input device that generated the input event. It can be one of the following values.

FAPPCOMMAND_KEY

User pressed a key.

FAPPCOMMAND_MOUSE

User clicked a mouse button.

FAPPCOMMAND_OEM

An unidentified hardware source generated the event. It could be a mouse or a keyboard event.

Where dwKeys indicates whether various virtual keys are down. It can be one or more of the following values.

MK_CONTROL

The CTRL key is down.

MK_LBUTTON

The left mouse button is down.

MK_MBUTTON

The middle mouse button is down.

MK_RBUTTON

The right mouse button is down.

MK_SHIFT

The SHIFT key is down.

MK_XBUTTON1

The first X button is down.

MK_XBUTTON2

The second X button is down.

Return Value

If an application processes this message, it should return TRUE. For more information about processing the return value, see the Remarks section.

Remarks

DefWindowProc generates the WM_APPCOMMAND message when it processes the WM_XBUTTONUP or WM_NCXBUTTONUP message, or when the user types an application command key.

If a child window does not process this message and instead calls DefWindowProc, DefWindowProc will send the message to its parent window. If a top level window does not process this message and instead calls DefWindowProc, DefWindowProc will call a shell hook with the hook code equal to HSHELL_APPCOMMAND.

To get the coordinates of the cursor if the message was generated by a button click on the mouse, the application can call GetMessagePos. An application can test whether the message was generated by the mouse by checking whether lParam contains FAPPCOMMAND_MOUSE.

Unlike other windows messages, an application should return TRUE from this message if it processes it. Doing so will allow software that simulates this message on Microsoft Windows systems earlier than Windows 2000 to determine whether the window procedure processed the message or called DefWindowProc to process it.

Notification Requirements

Minimum DLL Version	None
Header	Declared in Winuser.h, include Windows.h
Minimum operating systems	Millennium, Windows 2000

See Also

Mouse Input Overview, DefWindowProc, GET_APPCOMMAND_LPARAM, GET_DEVICE_LPARAM, GET_KEYSTATE_LPARAM, ShellProc, WM_XBUTTONUP, WM_NCXBUTTONUP