内工作空间，创建内存图层、图层透明度设置

      IWorkspaceFactory pwsf = new InMemoryWorkspaceFactoryClass();
            IWorkspaceName pWSName = pwsf.Create("", "temp", null, 0);
            IName pName = pWSName as IName;

            IWorkspace pMemoryWS = pName.Open() as IWorkspace;

      IFeatureClass oFeatureClass = (pMemoryWS as IFeatureWorkspace).CreateFeatureClass("Temp", Fields, null, null, esriFeatureType.esriFTSimple, "SHAPE", "")

   //透明度

           ILayerEffects pLyrEffect = oFeatureLayer as ILayerEffects;
                
           pLyrEffect.Transparency = 80;

有知道内存图层有什么用的吗？