学步园

        /// <summary>
        /// 改变地图显示的范围
        /// </summary>
        /// <param name="pPoint">点</param>
        ///<param name="dx">x方向放大比例</param>
        ///<param name="dy">y方向放大比例</param>
        private void ChangeEnvelope(IPoint pPoint,double dx,double dy)
        {
            if (activeView == null)
            {
                activeView = this.MapControl.ActiveView.FocusMap as IActiveView;
            }
            //范围
            IEnvelope pEnvelope = new EnvelopeClass();
            //获取焦点视图的范围
            pEnvelope = activeView.FullExtent;
            //重设范围的中心
            pEnvelope.CenterAt(pPoint);
            //放大范围
            pEnvelope.Expand(dx, dy, true);
            //更新地图范围
            activeView.Extent = pEnvelope;
            //Refresh the graphics
            activeView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
        }