AE+C# 最短路径

C#+AE网络分析问题？
namespace NetworkAnalysis
{
    public partial class Form1 : Form
    {
        //定义几何网络
        public IGeometricNetwork m_ipGeometricNetwork;
        public IPointCollection m_ipPoints;
        public IPointToEID m_ipPointToEID;
        public IEnumNetEID m_ipEnumNetEID_Junctions;
        
        public IEnumNetEID m_ipEnumNetEID_Edges;
        IPolyline m_ipPolyline;
        public Form1()
        {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            string str;
            //此处修改存储几何网络的Personal Geodatabase的名称和路径
            str = @"D:\二次开发实习\例子数据\网络数据\USA_Highway_Network Geodatabase.mdb";
            IWorkspaceFactory m_pWSF;
            IEnumDataset m_pEnumData;
            IDataset m_pDS;
            IEnumFeatureClass pEnumFC;
            m_pWSF=new AccessWorkspaceFactoryClass();
            IFeatureWorkspace m_pFWS;
            m_pFWS = m_pWSF.OpenFromFile(str, 0) as IFeatureWorkspace;
            IFeatureDataset m_pFDS;

            //此处修改存储几何网络的FeatureDataset的名称
            m_pFDS = m_pFWS.OpenFeatureDataset("high");
            m_pEnumData = m_pFDS.Subsets;
            m_pEnumData.Reset();
            m_pDS = m_pEnumData.Next();
            //此处修改几何网络的名称
            while (m_pDS.Name != "high_Net")
            {
                m_pDS = m_pEnumData.Next();
            }
            m_ipGeometricNetwork = m_pDS as IGeometricNetwork;
            pEnumFC = GetEnumNetFC(esriFeatureType.esriFTSimpleEdge);
            AddMapLayers(pEnumFC);
            pEnumFC=GetEnumNetFC(esriFeatureType.esriFTComplexEdge);
            AddMapLayers(pEnumFC);
            pEnumFC = GetEnumNetFC(esriFeatureType.esriFTSimpleJunction);
            AddMapLayers(pEnumFC);
            pEnumFC = null;
        }
        public IEnumFeatureClass GetEnumNetFC(esriFeatureType ftype)//定义GetEnumNetFC函数
        {
            IEnumFeatureClass pEnumFC;
            try
            {
                //GetEnumNetFC = null;
                if (m_ipGeometricNetwork == null)
                { return null; }
                pEnumFC = null;
                pEnumFC = m_ipGeometricNetwork.get_ClassesByType(ftype);
                if (pEnumFC == null)