添加点标注IMarkerElement

private void AddPointElement(IPoint pPoint)
        {
            if (pPoint != null)
            {
                IElement pElement = null;
                IRgbColor pColor = new RgbColorClass();
                pColor.Green = 255;

                double pSize = Math.Round(7200 / this.axMapControl1.MapScale, 2);
                if (pSize < 1)
                    pSize = 1;
                if (pSize > 20)
                    pSize = 20;

                IMarkerElement pMarkerElement = new MarkerElementClass();
                ISimpleMarkerSymbol pMarkerSymbol = new SimpleMarkerSymbolClass();
                pMarkerSymbol.Color = pColor;
                pMarkerSymbol.Angle = 0;
                pMarkerSymbol.Size = pSize;
                pMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;

                pMarkerElement.Symbol = pMarkerSymbol;
                pElement = pMarkerElement as IElement;
                pElement.Geometry = pPoint;

                this.axMapControl1.ActiveView.GraphicsContainer.AddElement(pElement, 0);
                this.axMapControl1.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, this.axMapControl1.ActiveView.Extent);
                
                }
        }