WinForm Mouse wheel Control custom scroll bar

Scenario: In a form similar to QQ chat, you need to add a custom scroll bar vscroll. The panel holds space in the main form, and the vertical scroll bar vscroll on the right.

Problem: The VScroll and Panel.verticalscroll scroll bars have been implemented, but the mouse wheel event cannot be triggered.

Cause: Panel cannot focus, the wheel event cannot be triggered after a mouse click.

Workaround: After clicking on the panel, VScroll gets the focus and then customizes the mouse wheel event.

Code:

//Mouse Wheel Eventprotected Override voidOnMouseWheel (MouseEventArgs e) {Base.     OnMouseWheel (e); if(E.delta <0) {Vscrollbar.value+=Vscrollbar.largechange; }         Else{Vscrollbar.value-=Vscrollbar.largechange; } mPanel.VerticalScroll.value=Vscrollbar.value;}//VScroll get focus after clicking panelPrivate voidPanel_click (Objectsender, EventArgs e)  {Vscrollbar.focus (); }

WinForm Mouse wheel Control custom scroll bar