cefsharp鼠标事件不工作？

public Form3(string strUrl)
{
InitializeComponent();
SetStyle(ControlStyles.UserPaint, true);
SetStyle(ControlStyles.AllPaintingInWmPaint, true); // 禁止擦除背景.

SetStyle(ControlStyles.DoubleBuffer, true); // 双缓冲

str = strUrl.ToString();
wb = new CefSharp.WinForms.ChromiumWebBrowser(str);

        wb.MenuHandler = new MenuHandler1();
        wb.LifeSpanHandler = new LifeSpanHandler1();
        wb.Dock = DockStyle.Fill;
        this.Controls.Add(wb);

        wb.MouseDown += Wb_MouseDown;
    }

    private void Wb_MouseDown(object sender, MouseEventArgs e)
    {
        textBox1.Text = "2222";
        throw new NotImplementedException();
    }

我也遇到了。楼主怎么解决的？？