SceneControl+AE+鼠标滚轮缩放

要为SceneControl设置鼠标滚轮缩放必须定义委托，因为SceneControl没有Wheel事件，所以委托From的Wheel事件

public Form1()
{
       InitializeComponent();
       this.MouseWheel += new MouseEventHandler(this.SceneControl_MouseWheel); //在这个地方输入"this.MouseWheel+=”后连续按两次Tab键
}
private void SceneControl_MouseWheel(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            try
            {
                axSceneControl1.MousePointer = esriControlsMousePointer.esriPointerZoom;
                System.Drawing.Point pSceneLocation = axSceneControl1.PointToScreen(axSceneControl1.Location);
                System.Drawing.Point Pt = axSceneControl1.PointToScreen(e.Location);
                if (Pt.X < pSceneLocation.X | Pt.X > pSceneLocation.X + axSceneControl1.Width | Pt.Y < pSceneLocation.Y | Pt.Y > pSceneLocation.Y + axSceneControl1.Height)
                    return;
                double scale = 0.2;
                if (e.Delta < 0) scale = -0.2;
                ICamera pCamera = axSceneControl1.Camera;
                IPoint pObserver = pCamera.Observer;
                IPoint pTarget = pCamera.Target;
                pObserver.X += (pObserver.X - pTarget.X) * scale;
                pObserver.Y += (pObserver.Y - pTarget.Y) * scale;
                pObserver.Z += (pObserver.Z - pTarget.Z) * scale;
                pCamera.Observer = pObserver;
                axSceneControl1.SceneGraph.RefreshViewers();
                //this.Text = e.Delta.ToString();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }