ArcGIS UID的用法

{6CA416B1-E160-11D2-9F4E-00C04F6BC78E} IDataLayer
{40A9E885-5533-11d0-98BE-00805F7CED21} IFeatureLayer
{E156D7E5-22AF-11D3-9F99-00C04F6BC78E} IGeoFeatureLayer
{34B2EF81-F4AC-11D1-A245-080009B6F22B} IGraphicsLayer
{5CEAE408-4C0A-437F-9DB3-054D83919850} IFDOGraphicsLayer
{0C22A4C7-DAFD-11D2-9F46-00C04F6BC78E} ICoverageAnnotationLayer
{EDAD6644-1810-11D1-86AE-0000F8751720} IGroupLayer

IMap.get_Layers(UID uid,bool recursive)
UID表示图层类型的GUID编码
recursive为true时候返回group layers里面的图层

例子：
////////////////////////////////////////////////////////////////////////////////
//              UID uid = new UIDClass();                                     //
//              uid.Value = "{40A9E885-5533-11d0-98BE-00805F7CED21}";        //
//              IEnumLayer layers = axMapControl1.Map.get_Layers(uid, true);  //
//              ILayer layer = null;