public void ShowFeature(Predicate <System.Data.DataRow> p = null)
        {
            List <SharpMap.Geometries.Geometry> geometries = new List <SharpMap.Geometries.Geometry>();

            m_shapeFileData.Open();
            for (uint i = 0; i < m_shapeFileData.GetFeatureCount(); ++i)
            {
                SharpMap.Data.FeatureDataRow featureDataRow = m_shapeFileData.GetFeature(i);
                if (p == null || p(featureDataRow))
                {
                    geometries.Add(m_shapeFileData.GetGeometryByID(i));
                }
            }
            m_shapeFileData.Close();

            m_shapeLayer.DataSource = new GeometryFeatureProvider(geometries);
            if (myMap.Layers.IndexOf(m_shapeLayer) == -1)
            {
                myMap.Layers.Add(m_shapeLayer);
            }

            //myMap.ZoomToExtents();
        }