我如何才能使MouseWheel正常工作而不必先集中精力于表单？

Question

I have a form with only a ReportViewer control on it. When the form is displayed, if you click on the report you can then use the mouse wheel to scroll vertically.

I'd like to be able to scroll as soon as the form appears.

I've tried the following, but no dice...

    private void ReportViewer_Load(object sender, EventArgs e)
    {
        rptViewer.Focus();
    }

    private void ReportViewer_Activated(object sender, EventArgs e)
    {
        rptViewer.Focus();
    }

Answer 1

Put your code in the form's constructor, right after InitializeComponent(); :

rptViewer.Select();

Answer 2

Did you try calling rptView.Activate()?

Also it may be that your form is getting focus after the load event completes (I think I've had problems with that before). One solution is, although it is definitely not elegant, to create a single-use Timer that starts when your Load method runs, and fires after 1 ms, and then stops. When the Timer fires, it will activate/focus your ReportViewer.

You could also try adding a MouseWheel event handler to your form. When the event is fired, send a scroll message to your ReportViewer to scroll it up or down. Then it doesn't matter whether or not your ReportViewer has focus, it (should) always scroll when the form has focus.

Answer 3

设置rptViewer.Focus调用SendKeys.Send(Chr(Keys.Tab))将焦点从菜单移动到预览区域。