ArcEngine捕捉节点

不多BB，直接上代码

    public sealed class Snap : BaseTool
    {
        #region COM Registration Function(s)
        [ComRegisterFunction()]
        [ComVisible(false)]
        static void RegisterFunction(Type registerType)
        {
            // Required for ArcGIS Component Category Registrar support
            ArcGISCategoryRegistration(registerType);

            //
            // TODO: Add any COM registration code here
            //
        }

        [ComUnregisterFunction()]
        [ComVisible(false)]
        static void UnregisterFunction(Type registerType)
        {
            // Required for ArcGIS Component Category Registrar support
            ArcGISCategoryUnregistration(registerType);

            //
            // TODO: Add any COM unregistration code here
            //
        }

        #region ArcGIS Component Category Registrar generated code
        /// <summary>
        /// Required method for ArcGIS Component Category registration -
        /// Do not modify the contents of this method with the code editor.
        /// </summary>
        private static void ArcGISCategoryRegistration(Type registerType)
        {
            string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
            MxCommands.Register(regKey);
            ControlsCommands.Register(regKey);
        }
        /// <summary>
        /// Required method for ArcGIS Component Category unregistration -
        /// Do not modify the contents of this method with the code editor.
        /// </summary>
        private static void ArcGISCategoryUnregistration(Type registerType)
        {
            string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
            MxCommands.Unregister(regKey);
            ControlsCommands.Unregister(regKey);
        }

        #endregion
        #endregion

        private IHookHelper m_hookHelper = null;
        ISnappingFeedback feedback;//展示捕捉
        IPointSnapper pointsnapper; //点捕捉器
        ISnappingEnvironment pSnappingEnvironment;

        public Snap()
        {
            //
            // TODO: Define values for the public properties
            //
            base.m_category = "捕捉"; //localizable text 
            base.m_caption = "捕捉";  //localizable text 
            base.m_message = "This should work in ArcMap/MapControl/PageLayoutControl";  //localizable text
            base.m_toolTip = "捕捉";  //localizable text
            base.m_name = "";   //unique id, non-localizable (e.g. "MyCategory_MyTool")
            try
            {
                //
                // TODO: change resource name if necessary
                //
                string bitmapResourceName = GetType().Name + ".bmp";
                base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
                base.m_cursor = new System.Windows.Forms.Cursor(GetType(), GetType().Name + ".cur");
            }
            catch (Exception ex)
            {
                System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
            }
        }

        #region Overridden Class Methods

        /// <summary>
        /// Occurs when this tool is created
        /// </summary>
        /// <param name="hook">Instance of the application</param>
        public override void OnCreate(object hook)
        {
            try
            {
                m_hookHelper = new HookHelperClass();
                m_hookHelper.Hook = hook;
                if (m_hookHelper.ActiveView == null)
                {
                    m_hookHelper = null;
                }
            }
            catch
            {
                m_hookHelper = null;
            }

            if (m_hookHelper == null)
                base.m_enabled = false;
            else
                base.m_enabled = true;
        }

        /// <summary>
        /// Occurs when this tool is clicked
        /// </summary>
        public override void OnClick()
        {
            //获取捕捉环境
            IExtensionManager extensionManager = (m_hookHelper as IHookHelper2).ExtensionManager;
            if (extensionManager != null)
            {
                IExtension extension = extensionManager.FindExtension(new UIDClass
                {
                    Value = "{E07B4C52-C894-4558-B8D4-D4050018D1DA}" //捕捉
                });

                pSnappingEnvironment = extension as ISnappingEnvironment;
                pSnappingEnvironment.Enabled = true;           //开启捕捉                 
                pSnappingEnvironment.IgnoreIMSLayers = true;   //忽略服务底图

                pointsnapper = pSnappingEnvironment.PointSnapper;    //获取点捕捉器

                feedback = new SnappingFeedbackClass();       //捕捉反馈，初始化
                feedback.Initialize(m_hookHelper.Hook, pSnappingEnvironment, true);                          
            }          
        }

        public override void OnMouseDown(int Button, int Shift, int X, int Y)
        {
            IPoint point = m_hookHelper.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);  //地图点
            ISnappingResult snapResult = this.pointsnapper.Snap(point);        //根据地图点获取捕捉结果
            
            if (snapResult != null)
                point = snapResult.Location;

            /****************
            后续可以使用point执行相关操作
            *****************/
        }

        public override void OnMouseMove(int Button, int Shift, int X, int Y)
        {
            IPoint pointcurrentcoords = m_hookHelper.ActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(X, Y);
            ISnappingResult snapResult = this.pointsnapper.Snap(pointcurrentcoords);
            this.feedback.Update(snapResult, 0);     //显示捕捉到的点 
        }

        public override void OnMouseUp(int Button, int Shift, int X, int Y)
        {
            // TODO:  Add Snap.OnMouseUp implementation
        }
        #endregion
    }

 注：

扩展的UID可以从AO帮助Names and IDs----Extensions里查看。