Look at this:List<int> RecArray = new List<int>(); IQueryFilter pSDEQueryFilter = new QueryFilterClass(); pSDEQueryFilter.WhereClause = "enter the selection criteria here" //For example population > 50000 IFeatureCursor pSDEFeatureCursor; IFeature pSDEFeature; pSpatialWorkSpace = GetWorkSpace(m_GDBType); //Method that uses the code pattern for getting a geodatabase workspace. Code for this not included. IFeatureWorkspace pSDEFeatureWorkspace = (IFeatureWorkspace)pSpatialWorkSpace; IFeatureClass pSDEFeatureClass = pSDEFeatureWorkspace.OpenFeatureClass("the name of a feature class"); //Get a record count int SDE_TotalRecCount = pSDEFeatureClass.FeatureCount(pSDEQueryFilter); //Set up the cursor and get the results pSDEFeatureCursor = pSDEFeatureClass.Search(pSDEQueryFilter, true); pSDEFeature = pSDEFeatureCursor.NextFeature(); while (pSDEFeature != null) { RecArray.Add(Convert.ToInt32(pSDEFeature.get_Value(pSDEFeature.Fields.FindField("OID")))); pSDEFeature = pSDEFeatureCursor.NextFeature(); }