Common messages and meanings of Windows

Message Range Description 0 ~ wm_user–1 System messages Wm_user ~ 0x7FFF Custom window class integer messages Wm_app ~ 0xBFFF Application Custom Messages 0xc000 ~ 0xFFFF Application string Messages > 0xFFFF Apply retention for future systems Message name Value Meaning Wm_null 0x0000 Empty message, this message will be ignored by the receiving window Wm_create 0x0001 Application creates a window Wm_destroy 0x0002 A window is destroyed Wm_move 0x0003 Move a window Wm_size 0x0005 Change the size of a window Wm_activate 0x0006 A window is activated or inactive Wm_setfocus 0x0007 After gaining focus Wm_killfocus 0x0008 Lose focus Wm_enable 0x000A Generated when the application Enable state changes Wm_setredraw 0x000b Sets whether the window can be redrawn Wm_settext 0x000c The application sends this message to set the text of a window Wm_gettext 0x000d The application sends this message to copy the corresponding window's text to the buffer Wm_gettextlength 0x000e Gets the length of the text associated with a window (does not contain null characters) Wm_paint 0x000f require a window to redraw itself Wm_close 0x0010 Send a signal when a window or application is about to close Wm_queryendsession 0x0011 The user selects the End dialog box or the application calls the ExitWindows function itself Wm_quit 0x0012 Used to end a program run or an application calling the PostQuitMessage function to produce this message Wm_queryopen 0x0013 Sends this message to an icon when the user window restores the previous size position Wm_erasebkgnd 0x0014 When the window background must be erased (for example, when the window changes size) Wm_syscolorchange 0x0015 Send this message to all top-level windows when the system color changes Wm_endsession 0x0016 When the system process issues a WM_QUERYENDSESSION message, this message is sent to the application Wm_showwindow 0x0018 When the hidden or displayed window is sent this message to this window Wm_activateapp 0x001c When a window will be activated, the window will be activated and the current activity (about to lose the activation) window will receive this message, sending this message to the application which window is active, which is the inactive Wm_fontchange 0x001d This message is sent to all top-level windows when the system's font repository changes Wm_timechange 0x001e Send this message to all top-level windows when the system's time changes Wm_cancelmode 0x001f Send this message to cancel an operation that is in progress Wm_setcursor 0x0020 If the mouse causes the cursor to move through a window and the mouse input is not captured, send a message to the window Wm_mouseactivate 0x0021 When the cursor is in a non-activated window and the user is pressing a key on the mouse to send this message to the current window Wm_childactivate 0x0022 Send this message to the MDI child window when the user taps the title bar of this window, or when the window is activated, moved, resized Wm_queuesync 0x0023 This message is sent by a computer-based training program that separates the user input message from the Wh_journalpalyback Hook program Wm_getminmaxinfo 0x0024 When the window is going to change size or position, send this message to the window Wm_painticon 0x0026 When the window icon is going to be redrawn, send this message to the window Wm_iconerasebkgnd 0x0027 This message is sent to the window when the icon background must be redrawn before the icon in a minimized window is redrawn Wm_nextdlgctl 0x0028 Send this message to a dialog box program to change the focus location Wm_spoolerstatus 0x002a This message is emitted when a print management queue increases or decreases a job Wm_drawitem 0x002b When the appearance of the Button,combobox,listbox,menu control changes, this message is sent to the owner of these controls Wm_measureitem 0x002c When the Button,combobox,list box,listview,menu item is created, this message is sent to the owner of the control Wm_deleteitem 0x002D When a ListBox or ComboBox is destroyed or when certain items are deleted by sending lb_deletestring, Lb_resetcontent, cb_deletestring, cb_resetcontent messages, Send this message to the owner of the control Wm_vkeytoitem 0x002e A ListBox control with a lbs_wantkeyboardinput style sends this message to its owner in response to the WM_KEYDOWN message Wm_chartoitem 0x002f A ListBox control with a lbs_wantkeyboardinput style sends this message to its owner in response to the WM_CHAR message Wm_setfont 0x0030 When the application draws the control, this message is sent to get the text in the control in which font is drawn Wm_getfont 0x0031 The application sends this message to get the font of the current control drawing text Wm_sethotkey 0x0032 The application sends this message to have a window associated with a hotkey Wm_gethotkey 0x0033 The application sends this message to determine if a hot key is associated with a window Wm_querydragicon 0x0037 This message is sent to the minimized window, and when the window is about to be dragged and the icon is not defined in its class, the application returns an icon or a handle to the cursor that the system displays when the user drags and puts the icon Wm_compareitem 0x0039 Send this message to determine the relative position of the newly added item in the ComboBox or ListBox Wm_compacting 0x0041 Display memory is very low. Wm_windowposchanging 0x0046 When the SetWindowPos function is called to change the size and position of the window, send this message to the window Wm_power 0x0048 This message is sent to all processes when the system will go into a pending state Wm_copydata 0x004a This message is sent when an application passes data to another application Wm_canceljournal 0x004b When a user cancels the program Log activation state, this message is sent to the application Wm_notify 0x004e Sends this message to its parent window when an event for a control has already occurred or if the control needs to get some information Wm_inputlangchangerequest 0x0050 When the user chooses an input language, or the hotkey of the input language changes Wm_inputlangchange 0x0051 Send this message to the affected top-level window when the application input language changes Wm_tcard 0x0052 Send this message to the application when the application has initialized the Windows help routine Wm_help 0x0053 When the user presses F1, if a menu is active, send this message to the menu associated with the window, otherwise it will be sent to the focus window, and if there is no focus, send the message to the currently active window Wm_userchanged 0x0054 When the user has logged in or exited to send this message to all windows, when the user logs on or exits the system updates the user's specific settings information, the system sends this message as soon as the user updates the settings Wm_notifyformat 0x0055 This message is used by common controls and their parent window to determine whether the structure is in ANSI or UNICODE form in the WM_NOTIFY message, which enables the control to communicate with its parent control Wm_contextmenu 0x007b When the user clicks the right button in a window, this message is sent to the window Wm_stylechanging 0x007c When you are about to invoke one or more styles of the SetWindowLong function window, send this message to the window Wm_stylechanged 0x007d When the call SetWindowLong function changes one or more styles of the window, send this message to the window Wm_displaychange 0x007e Send this message to all windows when the resolution of the monitor changes Wm_geticon 0x007F Send this message to a window that returns a handle to a large icon or small icon associated with a window Wm_seticon 0x0080 The application sends this message to have a new large icon or small icon associated with a window Wm_nccreate 0x0081 When a window is first created, this message is sent before the WM_CREATE message is sent Wm_ncdestroy 0x0082 This message notifies a window that the non-client area is being destroyed Wm_nccalcsize 0x0083 This message is sent when calculating the client area size and location of a window Wm_nchittest 0x0084 Generate this message when you move the mouse, press and hold or release the mouse Wm_ncpaint 0x0085 When a window's frame must be drawn, the application sends this message to the window Wm_ncactivate 0x0086 This message is sent to a window by changing its non-client area to indicate whether the window is active or inactive Wm_ncmousemove 0x00a0 This message is sent to the window when the cursor moves within the window's non-client area (window title bar and border) Wm_nclbuttondown 0x00A1 This message is sent when the cursor is in the non-client area of the window and the left mouse button is pressed Wm_nclbuttonup 0x00a2 This message is sent when the cursor is in the non-client area of the window and the left mouse button is released Wm_nclbuttondblclk 0x00a3 This message is sent when the cursor is in the non-client area of the window and the left mouse button is double-clicked Wm_ncrbuttondown 0x00a4 This message is sent when the cursor is in the non-client area of the window and the right mouse button is pressed Wm_ncrbuttonup 0x00a5 This message is sent when the cursor is in the non-client area of the window and the right mouse button is released Wm_ncrbuttondblclk 0x00a6 This message is sent when the cursor is in the non-client area of the window and the right mouse button is double-clicked Wm_ncmbuttondown 0x00a7 This message is sent when the cursor is in the non-client area of the window and the middle mouse button is pressed Wm_ncmbuttonup 0x00a8 This message is sent when the cursor is in the non-client area of the window and releases the middle mouse button Wm_ncmbuttondblcl 0x00a9 This message is sent when the cursor is in the non-client area of the window and the middle mouse button is double-clicked Wm_keydown 0x0100 Press a non-system key (the "ALT" key is not pressed when the key is pressed) Wm_keyup 0x0101 Release a non-system key Wm_char 0x0102 Press a key to send this message when TranslateMessage forwards Wm_keydown Wm_deadchar 0x0103 Release a key, send this message when TranslateMessage forwards Wm_keyup Wm_syskeydown 0x0104 Send this message to a window that has keyboard focus when you hold down the ALT key while pressing another key Wm_syskeyup 0x0105 Send this message to a window that has keyboard focus when releasing a key while holding down the ALT key Wm_syschar 0x0106 Send this message to a window that has keyboard focus when the TranslateMessage function forwards Wm_syskeydown Wm_sysdeadchar 0x0107 Send this message to a window that has keyboard focus when the TranslateMessage function forwards Wm_syskeyup Wm_initdialog 0x0110 Send this message dialog box before it is displayed, typically using this message to initialize the control and perform other tasks Wm_command 0x0111 This message is generated when you select a Window menu item or a control to send a message to its parent window or to press a shortcut key Wm_syscommand 0x0112 When you select a Window menu item or select Maximize or minimize, this message is sent to the window Wm_timer 0x0113 A timer event has occurred Wm_hscroll 0x0114 This message is sent to the owner of the window and scroll bar when the window horizontal scrollbar produces a scrolling event Wm_vscroll 0x0115 This message is sent to the owner of the window and scroll bar when the window vertical scrollbar produces a scrolling event Wm_initmenu 0x0116 This message is sent when a menu is about to be activated, it occurs when a menu item is pressed, or when a menu shortcut is pressed, which allows the program to change the menu before it is displayed Wm_initmenupopup 0x0117 This message is sent when a drop-down menu or submenu is about to be activated, allowing it to be displayed before the menu is modified without having to change the entire menu Wm_menuselect 0x011f Send this message to the owner of the menu when a menu item is selected (typically a window) Wm_menuchar 0x0120 When the menu is activated and the user presses a key (non-accelerator), the message is sent to the owner of the menu Wm_enteridle 0x0121 Sends this message to its owner when a modal dialog box or menu enters an idle state, which means that the message queue is empty after one or several previous messages have been processed Wm_menurbuttonup 0x0122 When the cursor is over a menu item, release the right mouse button to generate this message Wm_menudrag 0x0123 When you drag a menu item, this message is sent to the owner of the drag-and-drop menu Wm_menugetobject 0x0124 Send this message to the owner of the drop-down menu when the cursor moves into the menu item or moves from the center of the menu item to the top or bottom of the item Wm_uninitmenupopup 0x0125 This message is generated when the drop-down menu or submenu is destroyed Wm_menucommand 0x0126 This message is generated when the user selects a menu item Wm_changeuistate 0x0127 The application sends this message indicating that the user interface (UI) state should be changed Wm_updateuistate 0x0128 The application sends this message to change the user interface (UI) state of the specified window and its child windows Wm_queryuistate 0x0129 The application sends this message to get the user interface (UI) state of a window Wm_ctlcolormsgbox 0x0132 Sends this message to its parent window before the message box is drawn, and in response to this message, the parent window can set the text and background color of the message box by using the handle of the given related display device Wm_ctlcoloredit 0x0133 Sends this message to its parent window before drawing the edit control, which can be used to set the text and background color of the edit box Wm_ctlcolorlistbox 0x0134 Sends this message to its parent window before drawing the ListBox control, which can be used to set the text and background color of the edit box Wm_ctlcolorbtn 0x0135 Sends this message to its parent window before drawing the button control, which can be used to set the text and background color of the edit box Wm_ctlcolordlg 0x0136 Sends this message to its parent window before drawing the dialog box, which can be used to set the text and background color of the edit box Wm_ctlcolorscrollbar 0x0137 Sends this message to its parent window before drawing the scrollbar control, which you can use to set the text and background color of the scroll bar control Wm_ctlcolorstatic 0x0138 Sends this message to its parent window before drawing a static control, which can be used to set the text and background color of a static control Wm_mousemove 0x0200 Mouse movement Wm_lbuttondown 0x0201 Press the left mouse button Wm_lbuttonup 0x0202 Release left mouse button Wm_lbuttondblclk 0x0203 Double click left mouse button Wm_rbuttondown 0x0204 Press the right mouse button Wm_rbuttonup 0x0205 Release the right mouse button Wm_rbuttondblclk 0x0206 Double-click the right mouse button Wm_mbuttondown 0x0207 Press the middle mouse button Wm_mbuttonup 0x0208 Release middle mouse button Wm_mbuttondblclk 0x0209 Double-click the middle mouse button WM_MouseWheel 0x020a Sends this message to the currently focused window when the mouse wheel is rotated Wm_parentnotify 0x0210 When the MDI child window is created or destroyed, or when the cursor is over a child window and the user presses the mouse button, the message is sent to its parent window Wm_entermenuloop 0x0211 Send this message to notify the application that the main window process has entered the menu mode loop Wm_exitmenuloop 0x0212 Send this message to notify the application that the main window process has exited the menu mode loop Wm_sizing 0x0214 Adjust window Large hours send this message to the window through which the application can monitor or modify the window size and position Wm_capturechanged 0x0215 When the window is set to not capture mouse events, this message is sent to the window Wm_moving 0x0216 When you move a window, this message is sent to the window through which the application can monitor or modify the window size and position Wm_powerbroadcast 0x0218 Send this message to the application to notify it about power management events Wm_devicechange 0x0219 Send this message to the application or device driver when the device's hardware configuration changes Wm_mdicreate 0x0220 The application sends this message to a multi-document client window to create an MDI child window Wm_mdidestroy 0x0221 The application sends this message to a multi-document client window to close an MDI child window Wm_mdiactivate 0x0222 The application sends this message to the multi-document Customer window to notify the client window to activate another MDI child window, and when the client window receives this message, it issues a wm_mdiactive message to the MDI child window (not activated) to activate it Wm_mdirestore 0x0223 The application sends this message to the MDI client window to notify the child window to revert to its original size Wm_mdinext 0x0224 The application sends this message to the MDI client window to activate the next or previous window Wm_mdimaximize 0x0225 The application sends this message to the MDI client window to maximize an MDI child window Wm_mditile 0x0226 The application sends this message to the MDI client window to re-arrange all MDI child windows in a tiled manner Wm_mdicascade 0x0227 The application sends this message to the MDI client window to cascade all MDI child windows Wm_mdiiconarrange 0x0228 The application sends this message to the MDI client window to rearrange all the minimized MDI child windows Wm_mdigetactive 0x0229 The application sends this message to the MDI client window to find the handle to the active child window Wm_mdisetmenu 0x0230 The application sends this message to the MDI client window using the MDI menu instead of the child window's menu Wm_entersizemove 0x0231 This message is sent to the window when the window enters the move or changes the size mode loop Wm_exitsizemove 0x0232 This message is sent to the window when the window exits the move or changes the size mode loop Wm_dropfiles 0x0233 This message is generated when a user drags a file in the application window Wm_mdirefreshmenu 0x0234 The application sends this message to the MDI client window to refresh the Window menu Wm_mousehover 0x02a1 When the cursor hovers over the window client area beyond the time specified by the TrackMouseEvent function, this message is sent to the window Wm_mouseleave 0x02a3 This message is sent to the window when the cursor leaves the window client area longer than the time specified by the TrackMouseEvent function Wm_cut 0x0300 The application sends this message to an edit box or ComboBox to delete the currently selected text Wm_copy 0x0301 The application sends this message to an edit box or ComboBox to copy the currently selected text to the Clipboard Wm_paste 0x0302 The application sends this message to an edit box or ComboBox to get the data from the Clipboard Wm_clear 0x0303 The application sends this message to an edit box or ComboBox to clear the currently selected content Wm_undo 0x0304 The application sends this message to an edit box or ComboBox to undo the last action Wm_destroyclipboard 0x0307 When the EmptyClipboard function is called to empty the Clipboard, this message is sent to the clipboard owner Wm_drawclipboard 0x0308 When the contents of the Clipboard are changed, this message is sent to the first window in the Clipboard Watch chain, which allows the Clipboard viewing window to display new contents of the Clipboard Wm_paintclipboard 0x0309 This message is sent to the Clipboard owner when the Clipboard contains data in Cf_ownerdiplay format and the client area of the Clipboard Watch window needs to be redrawn Wm_vscrollclipboard 0x030a When the Clipboard contains Cf_ownerdiplay formatted data and the Clipboard Watch window has a vertical scrollbar event, the Clipboard Watch window sends this message to the Clipboard owner Wm_sizeclipboard 0x030b When the Clipboard contains data in cf_ownerdiplay format and the size of the client area of the Clipboard Watch window has changed, the Clipboard Watch window sends this message to the owner of the Clipboard Wm_askcbformatname 0x030c Clipboard Watch Window sends this message to the Clipboard owner to get the name of the Cf_ownerdisplay Clipboard format Wm_changecbchain 0x030d Send this message to the first window in the Clipboard watch chain when a window is removed from the Clipboard watch chain Wm_hscrollclipboard 0x030e The Clipboard Watch window sends this message to the Clipboard owner when the Clipboard contains Cf_ownerdiplay formatted data and the Clipboard Watch window has a horizontal scrollbar event Wm_querynewpalette 0x030f Send this message to the window that will get the keyboard focus, which gives the window a chance to implement its logical palette while gaining focus Wm_paletteischanging 0x0310 The application will implement its logical palette when sending this message to notify all applications Wm_palettechanged 0x0311 The window that gets the focus implements its logical palette after sending this message to all top-level and overlapping windows to change the system palette Wm_hotkey 0x0312 This message is generated when the user presses a hotkey registered by the RegisterHotKey function Wm_print 0x0317 The application sends this message to the window, requiring the window to draw itself in the specified device environment, typically the printer device environment Wm_printclient 0x0318 The application sends this message to the window, requiring the window to draw windows in the specified device Environment client area, typically the printer device environment Wm_app 0x8000 Help users customize messages, custom messages can be wm_app+x,x as positive integers Wm_user 0x0400 Help users customize messages, custom messages can be wm_user+x,x as positive integers

Common messages and meanings of Windows