一起学习ArcEngine（4）平移

地图平移，可以说是最重要的功能之一，许多地图的默认工具就是平移。AE实现平移，比较简单，代码如下

  /// <summary>
    ///  地图漫游工具
    /// </summary>
    public class Pan : GISTools.Base.ToolBase
    {

        private bool m_PanOperation;

        public Pan()
            : base("Pan")
        { }

        public Pan(AxMapControl mapCtl)
            : base(mapCtl, "Pan")
        {
            if (m_cursor == null) m_cursor = getCursor(esriSystemMouseCursor.esriSystemMouseCursorPan);
        }

        public Pan(AxPageLayoutControl plCtl)
            : base(plCtl, "Pan")
        {
            if (m_cursor == null) m_cursor = getCursor(esriSystemMouseCursor.esriSystemMouseCursorPan);
        }

        public override void OnMouseDown(int Button, int Shift, int X, int Y)
        {
            if (Button != 1) return;
           IPoint point =m_pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);
           m_pActiveView.ScreenDisplay.PanStart(point);
            m_PanOperation = true;
        }

        public override void OnMouseMove(int Button, int Shift, int X, int Y)
        {
            if (Button != 1) return;

            if (!m_PanOperation) return;

            IPoint point = m_pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);
            m_pActiveView.ScreenDisplay.PanMoveTo(point);
        }

        public override void OnMouseUp(int Button, int Shift, int X, int Y)
        {
            if (Button != 1) return;

            if (!m_PanOperation) return;

            IEnvelope extent = m_pActiveView.ScreenDisplay.PanStop();

            if (extent != null)
            {
                m_pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds = extent;
                m_pActiveView.ScreenDisplay.Invalidate(null, true, (short)esriScreenCache.esriAllScreenCaches);
            }
            m_PanOperation = false;
        }
    }