void CalcLength(string tmpshp)

        {

            var expression = "float(!SHAPE.LENGTH@YARDS!)";

            CalculateField cgridX = new CalculateField(tmpshp, "Length", expression);

            cgridX.expression_type = "PYTHON";

            IGeoProcessorResult gpResX = gp.Execute(cgridX, null) as IGeoProcessorResult;

            Console.WriteLine("计算长度");

        }  var gp = new ESRI.ArcGIS.Geoprocessor.Geoprocessor();            gp.AddOutputsToMap = true;            gp.OverwriteOutput = true;            gp.TemporaryMapLayers = true;