ESRI.ArcGIS.ArcMapUI.IMxDocument mxd = ArcMap.Application.Document as ESRI.ArcGIS.ArcMapUI.IMxDocument;
            ESRI.ArcGIS.Carto.IMap map = mxd.FocusMap;
            for (int i = 0; i < map.LayerCount; i++)
            {
                ESRI.ArcGIS.Carto.ILayer lay = map.Layer[i];
                if (map.Layer[i].Name == "Street_Light")
                {
                    ESRI.ArcGIS.Carto.IFeatureLayer flay = lay as ESRI.ArcGIS.Carto.IFeatureLayer;
                    ESRI.ArcGIS.Carto.IFeatureSelection fsel = flay as ESRI.ArcGIS.Carto.IFeatureSelection;


                    ESRI.ArcGIS.Geodatabase.IQueryFilter qfltr = new ESRI.ArcGIS.Geodatabase.QueryFilterClass();
                    qfltr.WhereClause = "POLE_TYPE ='IRON'";
                    ESRI.ArcGIS.Geodatabase.IFeatureCursor cur = flay.Search(qfltr, true);
                    ESRI.ArcGIS.Geodatabase.IFeature fea = cur.NextFeature();
                    while (fea != null)
                    {


                        fsel.SelectFeatures(qfltr, ESRI.ArcGIS.Carto.esriSelectionResultEnum.esriSelectionResultAdd, true);
                        fea = cur.NextFeature();

                    }

                    mxd.ActiveView.Refresh();
                }
            }