Delphi 7 - 在窗体中处理嵌入式框架的MouseWheel事件？ [英] Delphi 7 - Handling MouseWheel events for Embedded Frames in Forms?

问题描述

对于某些框架，我希望滚动内容（或至少处理鼠标事件）。

我尝试过以下操作：

只需为每个框架分配OnMouseWheel事件处理程序

覆盖父窗体的MouseWheel事件：

 过程TFmReview.MouseWheelHandler（var Message ：TMessage）; 
 var Control：TControl; 
 begin 
控制：= ControlAtPos（ScreenToClient（SmallPointToPoint（TWMMouseWheel（Message）.Pos）），False，True）; 
如果Assigned（Control）和（Control<> ActiveControl）然后
 begin 
 ShowMessage（Control.Name）; 
 Message.Result：= Control.Perform（CM_MOUSEWHEEL，Message.WParam，Message.LParam）; 
如果Message.Result = 0，那么
 Control.DefaultHandler（Message）; 
 end else继承MouseWheelHandler（Message）; 
结束
  

不幸的是，似乎没有工作。

• 在情况1中，事件永远不会被触发，但父表单鼠标滚轮处理程序被触发。


• 在情况2中，接收焦点的控件是保存要发送滚轮事件的帧的面板。因此，简单来说，我如何将鼠标滚轮事件指向鼠标光标结束的最顶级控件（无论哪一方面）框架/父/表格等）？

  解决方案

  将鼠标滚轮处理推迟到 TWinControl 目前是鼠标光标，在您的主框架中覆盖 MouseWheelHandler 方法使用如下代码：

   键入
   TMainForm = class（TForm） 
   private 
   procedure MouseWheelHandler（var AMessage：TMessage）;覆盖
   public 
   {公开声明} 
   end; 
   
  实现
   
  程序TMainForm.MouseWheelHandler（var AMessage：TMessage）; 
   var 
  控制：TWinControl; 
   begin 
  控制：= FindVCLWindow（SmallPointToPoint（TWMMouseWheel（AMessage）.Pos））; 
  如果分配（控制）然后
   begin 
   AMessage.Result：= Control.Perform（CM_MOUSEWHEEL，AMessage.WParam，
   AMessage.LParam）; 
  如果AMessage.Result = 0然后
   Control.DefaultHandler（AMessage）; 
   end 
   else 
  继承了MouseWheelHandler（AMessage）; 
  结束
    

  
  

  Hi I have a form with several frames inside.

  For some of the frames, i wish to scroll the contents (or at least handle the mousewheel event).

  I have tried the following:

  Simply assigning a OnMouseWheel event handler for each frame

  Overriding the MouseWheel event for the parent form:

  procedure TFmReview.MouseWheelHandler(var Message: TMessage);
  var   Control: TControl;
  begin
      Control := ControlAtPos(ScreenToClient(SmallPointToPoint(TWMMouseWheel(Message).Pos)), False, True);
      if Assigned(Control) and (Control <> ActiveControl) then
      begin
           ShowMessage(Control.Name);
           Message.Result := Control.Perform(CM_MOUSEWHEEL, Message.WParam, Message.LParam);
           if Message.Result = 0 then
              Control.DefaultHandler(Message);
       end else inherited MouseWheelHandler(Message);
  end;
  

  Unfortunately both dont seem to work.

  • In case 1, the event is never triggered, however the parent forms mouse wheel handler is triggered.
  • In case 2, the control that receives focus is the panel that holds the frame i wish to send the mousewheel event to.

  So, put simply, how can i direct the mousewheel event to the top most control that the mouse cursor is over (regardless of which frame/parent/form etc the cursor is in)?

  解决方案

  To postpone mouse wheel handling to a TWinControl over which is currently mouse cursor, override in your main frame form the MouseWheelHandler method using a code like this:

  type
    TMainForm = class(TForm)
    private
      procedure MouseWheelHandler(var AMessage: TMessage); override;
    public
      { Public declarations }
    end;
  
  implementation
  
  procedure TMainForm.MouseWheelHandler(var AMessage: TMessage);
  var
    Control: TWinControl;
  begin
    Control := FindVCLWindow(SmallPointToPoint(TWMMouseWheel(AMessage).Pos));
    if Assigned(Control) then
    begin
      AMessage.Result := Control.Perform(CM_MOUSEWHEEL, AMessage.WParam,
        AMessage.LParam);
      if AMessage.Result = 0 then
        Control.DefaultHandler(AMessage);
    end
    else
      inherited MouseWheelHandler(AMessage);
  end;
  

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