Avoid window getting focus

问题

I am working on a virtual keyboard the problem is when i press a key on the virtual keyboard the window witch the data needs to be sent loses focus. How can i avoid that ?

回答1:

When your keyboard form receives focus, part of the message it receives is the handle of the window that lost focus (wParam). Do what you need to do and set the focus back to the window that lost focus.

EDIT: See the documentation on WM_SETFOCUS

EDIT 2:

Also, you could use the following when creating your custom form:

procedure TMainForm.CreateParams(var Params: TCreateParams) ;
 //const WS_EX_NOACTIVATE = $8000000;
 begin
   inherited;
   Params.ExStyle := Params.ExStyle + WS_EX_NOACTIVATE;
 end;

To prevent your form from activating (taking focus from the other form). Like I alluded to in my comment, you should probably be using non-windowed controls for keys.

回答2:

The only method I've seen to do what you want is to disable the window with the virtual keyboard EnableWindow(hWnd, FALSE).

Now, if the window is disabled you will not get mouse messages, right? You have to options:

The easy one: Use WM_SETCURSOR. It is sent even to disabled windows, and in the high-order word of lParam you have the identifier of the original message (WM_LBUTTONDOWN, etc.). The coordinates of the cursor can be read using GetMessagePos().
The cool one: Use a windows hook: SetWindowsHookEx(WH_MOUSE, ...). You'll have full control of your mouse messages.

回答3:

Use a class that does not have the ability to gain keyboard focus, but only responds to mouse input.

Solution: Derive your virtual keyboard from TControl or TGraphicControl, and not from TWinControl or TCustomControl.

回答4:

Does this help?

procedure WMMouseActivate(var Message: TWMMouseActivate); message WM_MOUSEACTIVATE;

procedure TMyForm.WMMouseActivate(var Message: TWMMouseActivate);
begin
  Message.Result := MA_NOACTIVATE;
end;

来源：https://stackoverflow.com/questions/8125108/avoid-window-getting-focus

标签

Delphi

winapi