bool bCreateElement = true;

int internalTime = ;//时间间隔

int snapTime = ;//初始值

IElement m_element = null;  //界面绘制点元素

IPoint currentPoint = new PointClass();  //当前鼠标点

IPoint snapPoint = null;  //捕捉到的点

IMovePointFeedback pFeedback = new MovePointFeedbackClass();

public void DoMouseMove(object sender, IMapControlEvents2_OnMouseMoveEvent e)

{

    AxMapControl axMapControl1 = sender as AxMapControl;

    currentPoint.PutCoords(e.mapX, e.mapY);

    if (action == ActionType.CreateFeature)

    {

    snapTime++;

    snapTime = snapTime%internalTime ;

    ILayer layer = GetLayerByName(snapLayer, axMapControl1);

    IFeatureLayer m_iFeatureLyr = layer as IFeatureLayer;

    if (bCreateElement)

    {

    CreateMarkerElement(currentPoint,axMapControl1);

    bCreateElement = false;

    }

    if (snapPoint == null)

    ElementMoveTo(currentPoint, axMapControl1);

    //鼠标自动扑获顶点

    if (snapTime == )

    snapPoint = Snapping(e.mapX, e.mapY, m_iFeatureLyr,     axMapControl1);

    if (snapPoint != null && snapTime == )

    ElementMoveTo(snapPoint, axMapControl1);

    }

}

/// <summary>

/// 捕捉

/// </summary>

/// <param name=”x”></param>

/// <param name=”y”></param>

/// <param name=”iFeatureLyr”></param>

/// <param name=”axMapControl1″></param>

/// <returns></returns>

public IPoint Snapping(double x, double y, IFeatureLayer iFeatureLyr, AxMapControl axMapControl1)

{

    IPoint iHitPoint = null;

    IMap iMap = axMapControl1.Map;

    IActiveView iView = axMapControl1.ActiveView;

    IFeatureClass iFClss = iFeatureLyr.FeatureClass;

    IPoint point = new PointClass();

    point.PutCoords(x,y);

    double length =     ConvertPixelsToMapUnits(axMapControl1.ActiveView, );

    ITopologicalOperator pTopo = point as ITopologicalOperator;

    IGeometry pGeometry = pTopo.Buffer(length).Envelope as IGeometry;

    ISpatialFilter spatialFilter = new SpatialFilterClass();

    spatialFilter.GeometryField = iFeatureLyr.FeatureClass.ShapeFieldName;

    spatialFilter.SpatialRel = esriSpatialRelEnum.esriSpatialRelCrosses;

    spatialFilter.Geometry = pGeometry;

    IFeatureCursor cursor = iFClss.Search(spatialFilter, false);

    IFeature iF = cursor.NextFeature();

    if (iF == null) return null;

    IPoint iHitPt = new ESRI.ArcGIS.Geometry.Point();

    IHitTest iHitTest = iF.Shape as IHitTest;

    double hitDist = ;

    int partIndex = ;

    int vertexIndex = ;

    bool bVertexHit = false;

    // Tolerance in pixels for line hits

    double tol = ConvertPixelsToMapUnits(iView, );

    if (iHitTest.HitTest(point, tol, esriGeometryHitPartType.esriGeometryPartBoundary, iHitPt, ref hitDist, ref partIndex, ref vertexIndex, ref bVertexHit))

    {

　　　　iHitPoint = iHitPt;

    }

    axMapControl1.ActiveView.Refresh();

    return iHitPoint;

}

/// <summary>

/// 创建新的element用于显示

/// </summary>

/// <param name=”point”></param>

/// <param name=”axMapControl1″></param>

public void CreateMarkerElement(IPoint point, AxMapControl axMapControl1)

{

    IActiveView iView = axMapControl1.ActiveView;

    IGraphicsContainer iGraphContainer = axMapControl1.Map as IGraphicsContainer;

    //建立一个marker元素

    IMarkerElement iMarkerElement = new MarkerElement() as IMarkerElement;

    ISimpleMarkerSymbol iSym = new SimpleMarkerSymbol();

    //符号化元素

    IRgbColor iColor = new RgbColor();

    iColor.Red = ;

    iColor.Blue = ;

    iColor.Green = ;

    iSym.Color = iColor;

    IRgbColor iColor2 = new RgbColor();

    iColor2.Red = ;

    iColor2.Blue = ;

    iColor2.Green = ;

    iSym.Outline = true;

    iSym.OutlineColor = iColor2 as IColor;

    iSym.OutlineSize = ;

    iSym.Size = ;

    iSym.Style. = esriSimpleMarkerStyle.esriSMSCircle;

    ISymbol symbol = iSym as ISymbol;

    symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

    iMarkerElement.Symbol = iSym;

    m_element = iMarkerElement as IElement;

    m_element.Geometry = point as IGeometry;

    iGraphContainer.AddElement(m_element, );

    iView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, m_element, null);

    IGeometry iGeo = m_element.Geometry;

    pFeedback.Display = iView.ScreenDisplay;

    pFeedback.Symbol = iSym as ISymbol;

    pFeedback.Start(iGeo as IPoint, point);

}

/// <summary>

/// 移动元素

/// </summary>

/// <param name=”iPt”></param>

/// <param name=”axMapControl1″></param>

public void ElementMoveTo(IPoint iPt, AxMapControl axMapControl1)

{

    //移动元素

    pFeedback.MoveTo(iPt);

    IGeometry iGeo1 = null;

    IGeometry iGeoResult;

    if (m_element != null)

    {

　　iGeo1 = m_element.Geometry;

　　iGeoResult = pFeedback.Stop();

　　//map.ActiveView.Refresh();

　　m_element.Geometry = iGeoResult;

　　//更新该元素的位置

　　axMapControl1.ActiveView.GraphicsContainer.UpdateElement(m_element);

　　//重新移动元素

　　pFeedback.Start(iGeo1 as IPoint, iPt);

　　//map.ActiveView.Refresh();

　　axMapControl1.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);

    }

}

public ILayer GetLayerByName(string layerName, AxMapControl axMapControl1)

{

    for (int i = ; i < axMapControl1.LayerCount; i++)

    {

　　 if (axMapControl1.get_Layer(i).Name.Equals(layerName))

    　　return axMapControl1.get_Layer(i);

    }

    return null;

}

public double ConvertPixelsToMapUnits(IActiveView pActiveView, double pixelUnits)

{

    double realWorldDisplayExtent;

    int pixelExtent;

    double sizeOfOnePixel;

    pixelExtent = pActiveView.ScreenDisplay.DisplayTransformation.get_DeviceFrame().right – pActiveView.ScreenDisplay.DisplayTransformation.get_DeviceFrame().left;

    realWorldDisplayExtent = pActiveView.ScreenDisplay.DisplayTransformation.VisibleBounds.Width;

    sizeOfOnePixel = realWorldDisplayExtent / pixelExtent;

    return pixelUnits * sizeOfOnePixel;

}