C#判断点和直线的位置关系

        /// <summary>/// 判断点和直线的位置关系/// </summary>/// <param name="LinePntA">直线上的一点</param>/// <param name="LinePntB">直线上的另一点</param>/// <param name="PntM">需要判断的点</param>/// <returns></returns>private int JudgePointToLine(Point3d LinePntA, Point3d LinePntB, Point3d PntM){int nResult = 0;double ax = LinePntB.X - LinePntA.X;double ay = LinePntB.Y - LinePntA.Y;double bx = PntM.X - LinePntA.X;double by = PntM.Y - LinePntA.Y;double judge = ax * by - ay * bx;if (judge > 0){nResult = 1;}else if (judge < 0){nResult = -1;}else{nResult = 0;}return nResult;}