创建气泡

public IBalloonCallout CreateBallonCallout(double x, double y)
{
IRgbColor pRgbClr = new RgbColorClass();
pRgbClr.Red = 0;
pRgbClr.Green = 0;
pRgbClr.Blue = 255;
ISimpleFillSymbol pSmpFill = new SimpleFillSymbolClass();
pSmpFill.Color = pRgbClr;
pSmpFill.Style = esriSimpleFillStyle.esriSFSSolid;
IBalloonCallout pBllnCallout = new BalloonCalloutClass();
pBllnCallout.Style = esriBalloonCalloutStyle.esriBCSRectangle;
pBllnCallout.Symbol = pSmpFill;
pBllnCallout.LeaderTolerance = 1;
IPoint pPoint = new ESRI.ArcGIS.Geometry.PointClass();
pPoint.X = x;
pPoint.Y = y;
pBllnCallout.AnchorPoint = pPoint;
return pBllnCallout;
}