IOleInPlaceActiveObjectVB interface

A Visual Basic-style version of IOleInPlaceActiveObject.TranslateAccelerator, which a class can implement.

IOleInPlaceActiveObjectVB is not a Windows interface. It has the interface identifier 38584260-0CFB-45E7-8FBB-5D20B311F5B8 and extends stdole.IDispatch. It is not declared [OleAutomation(False)], as the package’s Windows interfaces are.

It exists because IOleInPlaceActiveObject has [PreserveSig] members, which a twinBASIC class cannot implement. This interface has one Sub that corresponds to the TranslateAccelerator method of that interface, with signature types that Visual Basic code uses.

Methods

TranslateAccelerator 

Sub TranslateAccelerator(ByRef Handled As Boolean, ByRef RetVal As Long, ByVal hWnd As LongPtr, ByVal wMsg As Long, ByVal wParam As LongPtr, ByVal lParam As LongPtr, ByVal Shift As Long)

Lets the object process an accelerator keystroke. The Windows method receives a pointer to a MSG structure; this one receives the fields of the message as separate parameters: the window handle hWnd, the message number wMsg, and wParam and lParam. Shift is passed in addition to them.

Handled and RetVal are passed by reference, and the implementation sets them. Handled is a flag that an implementation which dealt with the keystroke sets to True. RetVal corresponds to the HRESULT that the Windows method returns: S_OK (0) when the object used the keystroke and S_FALSE (1) when it did not.

Example

This class uses the F2 key (virtual-key code &H71) and reports that it did, with S_OK as the result. It leaves every other keystroke alone.

Class AcceleratorHandler
    Implements IOleInPlaceActiveObjectVB

    Private Sub IOleInPlaceActiveObjectVB_TranslateAccelerator(ByRef Handled As Boolean, ByRef RetVal As Long, ByVal hWnd As LongPtr, ByVal wMsg As Long, ByVal wParam As LongPtr, ByVal lParam As LongPtr, ByVal Shift As Long) Implements IOleInPlaceActiveObjectVB.TranslateAccelerator
        If wMsg = &H100 And wParam = &H71 Then
            Handled = True
            RetVal = 0
        End If
    End Sub
End Class

A key-down message for F2 (WM_KEYDOWN, &H100) is handled:

Dim a As IOleInPlaceActiveObjectVB = New AcceleratorHandler
Dim handled As Boolean
Dim result As Long = 1

a.TranslateAccelerator handled, result, 0, &H100, &H71, 0, 0
Debug.Print handled  ' True
Debug.Print result   ' 0

See Also