Windows apps
Collapse the table of content
Expand the table of content
Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

ITfKeystrokeMgr::KeyDown method

Syntax


HRESULT KeyDown(
  [in]  WPARAM wParam,
  [in]  LPARAM lParam,
  [out] BOOL   *pfEaten
);

Parameters

wParam [in]

Specifies the virtual-key code of the key. For more information about this parameter, see the wParam parameter in WM_KEYDOWN.

lParam [in]

Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag of the key. For more information about this parameter, see the lParam parameter in WM_KEYDOWN.

pfEaten [out]

Pointer to a BOOL that, on exit, indicates if the key event was handled. If this value receives TRUE, the key event was handled and the event should not be forwarded to the application. If this value is FALSE, the key event was not handled and the event should be forwarded to the application.

Return value

This method can return one of these values.

ValueDescription
S_OK

The method was successful.

S_FALSE

There are no key event sinks installed.

E_INVALIDARG

One or more parameters are invalid.

 

Remarks

If this method is successful and pfEaten receives TRUE, the application should not process the key down event. If this method does not return S_OK or pfEaten receives FALSE, the application should process the key down event. The following is an example of how this is implemented.


if(msg.message == WM_KEYDOWN)
{
    if( pKeyboardMgr->TestKeyDown(msg.wParam, msg.lParam, &fEaten) == S_OK 
        && fEaten 
        && pKeyboardMgr->KeyDown(msg.wParam, msg.lParam, &fEaten) == S_OK 
        && fEaten)
    {
        //The key was handled by the keystroke manager or a TSF text service. Do not pass the key to the application. 
        continue;
    }
    else
    {
        //Let the application process the key. 
    }
}

If the keystroke manager does not handle the key event, it passes the key event to TSF text services by calling the TSF text service ITfKeyEventSink::OnKeyDown method.

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps | Windows Store apps]

Minimum supported server

Windows 2000 Server [desktop apps | Windows Store apps]

Redistributable

TSF 1.0 on Windows 2000 Professional

Header

Msctf.h

IDL

Msctf.idl

DLL

Msctf.dll

See also

ITfKeystrokeMgr
ITfKeyEventSink::OnKeyDown
ITfKeystrokeMgr::KeyUp
ITfKeystrokeMgr::TestKeyDown
WM_KEYDOWN

 

 

Show:
© 2017 Microsoft