/// <summary>        /// 删除fieldName属性值为1的弧段        /// </summary>        /// <param name="fieldName"></param>        /// <param name="t"></param>        public void DelectPolyline(string fieldName, int t)        {            ILayer pLayer = axMapControl1.get_Layer(0);            IFeatureLayer pFeatureLayer = pLayer as IFeatureLayer;            IFeatureClass pFeatureClass = pFeatureLayer.FeatureClass;            IFields pIFields = pFeatureLayer.FeatureClass.Fields;            int fieldIndex = pIFields.FindField(fieldName);            var pDataset = pFeatureClass as IDataset;            IWorkspace pWorkspace = pDataset.Workspace;            IFeatureWorkspace pFWs = pWorkspace as IFeatureWorkspace;            IWorkspaceEdit pWorkspaceEdit = (IWorkspaceEdit)pFWs;            pWorkspaceEdit.StartEditing(true);            pWorkspaceEdit.StartEditOperation();            IFeatureCursor pEF = pFeatureLayer.Search(null, false);            IFeature pFeatureDe = pEF.NextFeature();            while (pFeatureDe != null)            {                if (Convert.ToInt32(pFeatureDe.get_Value(fieldIndex)) != t)                {                    pFeatureDe.Delete();                }                pFeatureDe = pEF.NextFeature();            }            pWorkspaceEdit.StopEditOperation();            pWorkspaceEdit.StopEditing(true);            MessageBox.Show("删除成功");        }

///若干个线要素合并成一个 private void MergeFeatures(List<int> OneFeatureArr,ILayer tSelectLayer)        {            IFeatureLayer tFeatureLayer = tSelectLayer as IFeatureLayer;            IFeatureClass pFeatureClass = tFeatureLayer.FeatureClass;            var pDataset = pFeatureClass as IDataset;            IWorkspace pWorkspace = pDataset.Workspace;            IFeatureWorkspace pFWs = pWorkspace as IFeatureWorkspace;                        IWorkspaceEdit pWorkspaceEdit = (IWorkspaceEdit)pFWs;            pWorkspaceEdit.StartEditing(true);            pWorkspaceEdit.StartEditOperation();            IFeatureLayer pFeatureLayer = tSelectLayer as IFeatureLayer;            IFeatureCursor pEF = pFeatureLayer.Search(null, false);            IFeature pFeatureFirst = pEF.NextFeature();            while (pFeatureFirst != null)            {//找到在数组里的第一个要素                if (pFeatureFirst.OID == OneFeatureArr[0])                {                    //OneFeatureArr.RemoveAt(0);//除掉第一个要素                    break;                }                else                    pFeatureFirst = pEF.NextFeature();            }            pEF = pFeatureLayer.Search(null, false);            IGeometry pGeometryFirst = pFeatureFirst.Shape;            ITopologicalOperator2 pTopOperatorFirst = (ITopologicalOperator2)pGeometryFirst;            IRelationalOperator pRelOperatorFirst = (IRelationalOperator)pGeometryFirst;            pTopOperatorFirst.IsKnownSimple_2 = false;            pTopOperatorFirst.Simplify();            pGeometryFirst.SnapToSpatialReference();            IGeometry pGeometrySecond = null;            IFeature pFeatureSecond = pEF.NextFeature();            IGeometryCollection Geometrybag = new GeometryBagClass();//装geometry的袋子            object oMissing = Type.Missing;            while (pFeatureSecond != null)            {                if (OneFeatureArr.IndexOf(pFeatureSecond.OID) == -1)                {                    pFeatureSecond = pEF.NextFeature();                    continue;                }                pGeometrySecond = pFeatureSecond.ShapeCopy;                Geometrybag.AddGeometry(pGeometrySecond, ref oMissing, ref oMissing);//将geometry装进袋子                //pFeatureSecond.Delete();                pFeatureSecond = pEF.NextFeature();            }            IEnumGeometry tEnumGeometry = (IEnumGeometry)Geometrybag;            pTopOperatorFirst.ConstructUnion(tEnumGeometry);            pTopOperatorFirst.IsKnownSimple_2 = false;            pTopOperatorFirst.Simplify();            pFeatureFirst.Shape = pGeometryFirst;                       pFeatureFirst.Store();                        pWorkspaceEdit.StopEditOperation();            pWorkspaceEdit.StopEditing(true);        }