AE如何获取Coordinate System修改的投影

我在ArcEngine里通过如下代码调出Coordinate System属性窗口（如图1），对坐标投影进行修改按确定后，我怎么可以获取到修改后的投影？？？

代码如下：

void CoordinateSystem(ILayer pLayer)
{
try
{
//IMap pMap = new MapClass();
//pMap.AddLayer(pLayer);

            IComPropertySheet PSheet = new ComPropertySheetClass();
            PSheet.HideHelpButton = true;

            ESRI.ArcGIS.esriSystem.ISet PSet = new ESRI.ArcGIS.esriSystem.SetClass();

            //PSet.Add(pMap);
            PSet.Add(pLayer);

            PSheet.ClearCategoryIDs();
            PSheet.AddCategoryID(new UIDClass());

            IPropertyPage APage = null;

            #region 数据框属性
            APage = new ESRI.ArcGIS.CartoUI.MapProjectionPropPageClass();//坐标系
            PSheet.AddPage(APage);
            #endregion

            PSheet.Title = "空间参考属性";

           //假如已经修改了内容，则更新地图
            if (PSheet.EditProperties(PSet, 0))
            {
                ISpatialReference pSpatialRef = ArcGIS.Feature.GetSpatialReference(((IFeatureLayer)pLayer).FeatureClass);
                string proName = pSpatialRef.Name;
            }
        }
        catch (Exception ex)
        {
        }
    }

图1如下：