delphi – TListView和鼠标滚轮滚动
发布时间:2020-12-15 10:07:44 所属栏目:大数据 来源:网络整理
导读:我在表单中有一个TListView组件.它很长,我希望用户能够滚动它,如果鼠标在组件上方并滚动滚轮.我没有为TListView对象找到任何OnMouseWheel,OnMouseWheelDown或OnMouseWheelUp事件.我怎样才能做到这一点? 问候, 恶者 解决方法 这是我的代码: type TMyListVie
我在表单中有一个TListView组件.它很长,我希望用户能够滚动它,如果鼠标在组件上方并滚动滚轮.我没有为TListView对象找到任何OnMouseWheel,OnMouseWheelDown或OnMouseWheelUp事件.我怎样才能做到这一点?
问候, 解决方法
这是我的代码:
type TMyListView = class(TListView) protected function DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean; override; function DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean; override; end; type TMouseWheelDirection = (mwdUp,mwdDown); function GenericMouseWheel(Handle: HWND; Shift: TShiftState; WheelDirection: TMouseWheelDirection): Boolean; var i,ScrollCount,Direction: Integer; Paging: Boolean; begin Result := ModifierKeyState(Shift)=[];//only respond to un-modified wheel actions if Result then begin Paging := DWORD(Mouse.WheelScrollLines)=WHEEL_PAGESCROLL; ScrollCount := Mouse.WheelScrollLines; case WheelDirection of mwdUp: if Paging then begin Direction := SB_PAGEUP; ScrollCount := 1; end else begin Direction := SB_LINEUP; end; mwdDown: if Paging then begin Direction := SB_PAGEDOWN; ScrollCount := 1; end else begin Direction := SB_LINEDOWN; end; end; for i := 1 to ScrollCount do begin SendMessage(Handle,WM_VSCROLL,Direction,0); end; end; end; function TMyListView.DoMouseWheelDown(Shift: TShiftState; MousePos: TPoint): Boolean; begin //don't call inherited Result := GenericMouseWheel(Handle,Shift,mwdDown); end; function TMyListView.DoMouseWheelUp(Shift: TShiftState; MousePos: TPoint): Boolean; begin //don't call inherited Result := GenericMouseWheel(Handle,mwdUp); end; GenericMouseWheel非常漂亮.它适用于任何带垂直滚动条的控件.我将它用于树视图,列表视图,列表框,备忘录,丰富的编辑等. 您将缺少我的ModifierKeyState例程,但您可以用自己的方法替换来检查wheel事件是否未被修改.你想要这样做的原因是,例如,CTRL鼠标滚轮意味着缩放而不是滚动. 对于它的价值,它看起来像这样: type TModifierKey = ssShift..ssCtrl; TModifierKeyState = set of TModifierKey; function ModifierKeyState(Shift: TShiftState): TModifierKeyState; const AllModifierKeys = [low(TModifierKey)..high(TModifierKey)]; begin Result := AllModifierKeys*Shift; end; (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |