WMMouseWheel不在Delphi中工作 [英] WMMouseWheel not working in Delphi

问题描述

我写了以下代码：
procedure MouseWheel（var Msg：TWMMouseWheel）; message WM_MOUSEHWHEEL;
我用它为基于TPanel（TMyP = class（TPanel））
（注意，由于我自己的原因，我不想使用TCustomPanel）

I wrote the following code: procedure MouseWheel(var Msg:TWMMouseWheel);message WM_MOUSEHWHEEL; I used it for a component based on TPanel (TMyP=class(TPanel)) (Notice that I don't want to use TCustomPanel due to my own reasons)

但无论如何，事件是当我在面板上使用鼠标滚轮时不调用。
请帮助我！

But anyway the event is not called when I use mouse wheel on the panel. Please Help me!

推荐答案

鼠标滚轮消息以焦点发送到控件。而且面板通常是不能对焦的。

The mouse wheel messages are sent to the control with the focus. And panels usually aren't focusable.

我在应用程序中使用这个TApplicationEvents.OnMessage处理程序将鼠标滚轮消息发送到鼠标光标下的窗口而不是焦点控制。

I use this TApplicationEvents.OnMessage handler in my applications to send the mouse wheel message to the window under the mouse cursor instead of the focused control.

procedure TMainDataModule.ApplicationEventsMessage(var Msg: tagMSG; var Handled: Boolean);
var
  Wnd: HWND;
begin
  if Msg.message = WM_MOUSEWHEEL then
  begin
    Wnd := WindowFromPoint(Msg.pt);
    // It must be a VCL control otherwise we could get access violations
    if IsVCLControl(Wnd) then
      Msg.hwnd := Wnd; // change the message receiver to the control under the cursor
  end;
end;

这篇关于WMMouseWheel不在Delphi中工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！