/// 
        /// Services the area.        /// 
        /// The network dataset.        public void ServiceArea(INetworkDataset networkDataset)        {            log.WriteLog("开始创建ServiceArea...");             IWorkspaceFactory workspaceFactory = new ShapefileWorkspaceFactoryClass();            IWorkspace workspace = workspaceFactory.OpenFromFile(Functions.g_WorkSpacePath, 0);            IFeatureWorkspace featureWorkspace = workspace as IFeatureWorkspace;                       CreateSolverContext(networkDataset);            if (!LoadLocations(featureWorkspace, Functions.g_Hospital))            {                log.WriteLog("LoadLocations失败！");            }             log.WriteLog("ServiceArea创建完成！");        } /// 
        /// Geodatabase function: get network dataset        /// 
        /// Input network dataset        /// 
     
      DE network dataset
             public IDENetworkDataset GetDENetworkDataset(INetworkDataset networkDataset)        {            // Cast from the network dataset to the DatasetComponent            IDatasetComponent dsComponent = networkDataset as IDatasetComponent;             // Get the data element            return dsComponent.DataElement as IDENetworkDataset;        }         /// 
        /// Create NASolver and NAContext        /// 
        /// Input network dataset        private void CreateSolverContext(INetworkDataset networkDataset)        {            if (networkDataset == null) return;             //Get the Data Element            IDENetworkDataset deNDS = GetDENetworkDataset(networkDataset);             INASolver naSolver = new NAServiceAreaSolverClass();            m_NAContext = naSolver.CreateContext(deNDS, naSolver.Name);            ((INAContextEdit)m_NAContext).Bind(networkDataset, new GPMessagesClass());        } /// 
        /// Loads the locations.        /// 
        /// The feature workspace.        /// The input facilities.        /// 
     
      
       true
       if XXXX, 
      
       false
       otherwise
             private bool LoadLocations(IFeatureWorkspace featureWorkspace, string inputFacilities)        {            IFeatureClass inputFeatureClass = null;            try            {                inputFeatureClass = featureWorkspace.OpenFeatureClass(inputFacilities);            }            catch (Exception)            {                log.WriteLog("Specified input feature class does not exist");                return false;            }             INamedSet classes = m_NAContext.NAClasses;            INAClass naClass = classes.get_ItemByName("Facilities") as INAClass;             // delete existing locations, except barriers            naClass.DeleteAllRows();             // Create a NAClassLoader and set the snap tolerance (meters unit)            INAClassLoader naClassLoader = new NAClassLoaderClass();            naClassLoader.Locator = m_NAContext.Locator;            ((INALocator3)naClassLoader.Locator).MaxSnapTolerance = 500;            naClassLoader.NAClass = naClass;             // Create field map to automatically map fields from input class to NAClass            INAClassFieldMap naClassFieldMap = new NAClassFieldMapClass();            naClassFieldMap.CreateMapping(naClass.ClassDefinition, inputFeatureClass.Fields);            naClassLoader.FieldMap = naClassFieldMap;             // Avoid loading network locations onto non-traversable portions of elements            INALocator3 locator = m_NAContext.Locator as INALocator3;            locator.ExcludeRestrictedElements = true;            locator.CacheRestrictedElements(m_NAContext);             // load network locations            int rowsIn = 0;            int rowsLocated = 0;            IQueryFilter qf = new QueryFilterClass();            qf.WhereClause = "aaaaaaaaaaa";              naClassLoader.Load(inputFeatureClass.Search(qf, true) as ICursor, null, ref rowsIn, ref rowsLocated);             if (rowsLocated <= 0)            {                log.WriteLog("Facilities were not loaded from input feature class");                return false;            }             // Message all of the network analysis agents that the analysis context has changed            INAContextEdit naContextEdit = m_NAContext as INAContextEdit;            naContextEdit.ContextChanged();             return true;        }