private IFeatureClass CreatePolylineFeatureClass(IFeatureWorkspace featWorkspace, string name)
{
IFieldsEdit pFldsEdt = new FieldsClass();
IFieldEdit pFldEdt = new FieldClass();
pFldEdt = new FieldClass();
pFldEdt.Type_2 = esriFieldType.esriFieldTypeOID;
pFldEdt.Name_2 = "OBJECTID";
pFldEdt.AliasName_2 = "OBJECTID";
pFldsEdt.AddField(pFldEdt);
IGeometryDefEdit pGeoDef;
pGeoDef = new GeometryDefClass();
pGeoDef.GeometryType_2 = esriGeometryType.esriGeometryPolyline;
pGeoDef.SpatialReference_2 = ArcMap.Document.FocusMap.SpatialReference;
pFldEdt = new FieldClass();
pFldEdt.Name_2 = "SHAPE";
pFldEdt.AliasName_2 = "SHAPE";
pFldEdt.Type_2 = esriFieldType.esriFieldTypeGeometry;
pFldEdt.GeometryDef_2 = pGeoDef;
pFldsEdt.AddField(pFldEdt);
IFeatureClass pFClass = featWorkspace.CreateFeatureClass(name, pFldsEdt, null, null, esriFeatureType.esriFTSimple, "SHAPE", "");
return pFClass;
}