private int CwpProc(int nCode, IntPtr wParam, IntPtr lParam)
{
CwpStruct cwpStruct = (CwpStruct)Marshal.PtrToStructure(lParam, typeof(CwpStruct));
if (nCode < 0)
{
return(WindowsInterop.CallNextHookEx(_hHookCwp, nCode, wParam, lParam));
}
if (cwpStruct.message == WindowsInterop.WM_MOUSEACTIVATE)
{
// We got a WM_MOUSEACTIVATE message. Now we will check that the target handle is a workbook window.
// Workbook windows have the name "EXCEL7".
bool isWorkbookWindow = false;
try
{
StringBuilder cname = new StringBuilder(256);
WindowsInterop.GetClassNameW(cwpStruct.hwnd, cname, cname.Capacity);
if (cname.ToString() == "EXCEL7")
{
isWorkbookWindow = true;
}
}
catch (Exception e)
{
Debug.Print("Could not get the window name: {0}", e);
}
if (isWorkbookWindow)
{
// If the window is not activated, then Excel will activate it and then discard the message. That's why the user cannot select a range at the same time.
// The following statement will activate the window before Excel treats the message, thus it will not activate the window and it will keep proceeding the message.
// In that way, it is possible to select the range.
try
{
WindowsInterop.SetFocus(cwpStruct.hwnd);
}
catch (Exception e)
{
Debug.Print("Failed to set the focus: {0}", e);
}
// If the user chooses a cell which was already selected, then the event SheetSelectionChange will not be raised.
// A workaround is to send the current selection when the Excel window gets the focus.
// Note that if the user selects a different range, then 2 events will be raised: a first one with the current selection,
// and a second one with the new selection.
try
{
OnNewSelection(null, (Range)_application.Selection);
}
catch
{
}
}
}
return(WindowsInterop.CallNextHookEx(_hHookCwp, nCode, wParam, lParam));
}
public void Stop()
{
_application.SheetSelectionChange -= OnNewSelection;
if (!WindowsInterop.UnhookWindowsHookEx(_hHookCwp))
{
Debug.Print("Error: Failed to unhook WH_CALLWNDPROC");
}
}
private readonly WindowsInterop.HookProc _procCwp; // Note: do not make this delegate a local variable within the ExcelSelectionTracker constructor because it must not be collected by the GC before the unhook
public ExcelSelectionTracker(int excelThreadId)
{
_application = (Application)ExcelDnaUtil.Application;
_application.SheetSelectionChange += OnNewSelection;
_procCwp = CwpProc;
_hHookCwp = WindowsInterop.SetWindowsHookEx(HookType.WH_CALLWNDPROC, _procCwp, (IntPtr)0, excelThreadId);
if (_hHookCwp == 0)
{
throw new Exception("Failed to hook WH_CALLWNDPROC");
}
}
public MyRibbon()
{
_excelThreadId = WindowsInterop.GetCurrentThreadId();
}