what's the difference between a layer's CLSID, GUID, and UID

[SeanNakasone]

Using the code snippet below, I'm confused about the terms CLSID, GUID, and UID in respect to layer objects.

Are they all the same thing?


///<summary>Stub code to loop through layers in a map where a specific UID is supplied.</summary>
///
///<param name="map">An IMap interface in which the layers reside.</param>
///<param name="layerCLSID">A System.String that is the layer GUID type. For example: "{E156D7E5-22AF-11D3-9F99-00C04F6BC78E}" is the IGeoFeatureLayer.</param>
///
///<remarks>In order of the code to be useful the user needs to write their own code to use the layer in the TODO section.
///
/// The different layer GUID's and Interface's are:
/// "{AD88322D-533D-4E36-A5C9-1B109AF7A346}" = IACFeatureLayer
/// "{74E45211-DFE6-11D3-9FF7-00C04F6BC6A5}" = IACLayer
/// "{495C0E2C-D51D-4ED4-9FC1-FA04AB93568D}" = IACImageLayer
/// "{65BD02AC-1CAD-462A-A524-3F17E9D85432}" = IACAcetateLayer
/// "{4AEDC069-B599-424B-A374-49602ABAD308}" = IAnnotationLayer
/// "{DBCA59AC-6771-4408-8F48-C7D53389440C}" = IAnnotationSublayer
/// "{E299ADBC-A5C3-11D2-9B10-00C04FA33299}" = ICadLayer
/// "{7F1AB670-5CA9-44D1-B42D-12AA868FC757}" = ICadastralFabricLayer
/// "{BA119BC4-939A-11D2-A2F4-080009B6F22B}" = ICompositeLayer
/// "{9646BB82-9512-11D2-A2F6-080009B6F22B}" = ICompositeGraphicsLayer
/// "{0C22A4C7-DAFD-11D2-9F46-00C04F6BC78E}" = ICoverageAnnotationLayer
/// "{6CA416B1-E160-11D2-9F4E-00C04F6BC78E}" = IDataLayer
/// "{0737082E-958E-11D4-80ED-00C04F601565}" = IDimensionLayer
/// "{48E56B3F-EC3A-11D2-9F5C-00C04F6BC6A5}" = IFDOGraphicsLayer
/// "{40A9E885-5533-11D0-98BE-00805F7CED21}" = IFeatureLayer
/// "{605BC37A-15E9-40A0-90FB-DE4CC376838C}" = IGdbRasterCatalogLayer
/// "{E156D7E5-22AF-11D3-9F99-00C04F6BC78E}" = IGeoFeatureLayer
/// "{34B2EF81-F4AC-11D1-A245-080009B6F22B}" = IGraphicsLayer
/// "{EDAD6644-1810-11D1-86AE-0000F8751720}" = IGroupLayer
/// "{D090AA89-C2F1-11D3-9FEF-00C04F6BC6A5}" = IIMSSubLayer
/// "{DC8505FF-D521-11D3-9FF4-00C04F6BC6A5}" = IIMAMapLayer
/// "{34C20002-4D3C-11D0-92D8-00805F7C28B0}" = ILayer
/// "{E9B56157-7EB7-4DB3-9958-AFBF3B5E1470}" = IMapServerLayer
/// "{B059B902-5C7A-4287-982E-EF0BC77C6AAB}" = IMapServerSublayer
/// "{82870538-E09E-42C0-9228-CBCB244B91BA}" = INetworkLayer
/// "{D02371C7-35F7-11D2-B1F2-00C04F8EDEFF}" = IRasterLayer
/// "{AF9930F0-F61E-11D3-8D6C-00C04F5B87B2}" = IRasterCatalogLayer
/// "{FCEFF094-8E6A-4972-9BB4-429C71B07289}" = ITemporaryLayer
/// "{5A0F220D-614F-4C72-AFF2-7EA0BE2C8513}" = ITerrainLayer
/// "{FE308F36-BDCA-11D1-A523-0000F8774F0F}" = ITinLayer
/// "{FB6337E3-610A-4BC2-9142-760D954C22EB}" = ITopologyLayer
/// "{005F592A-327B-44A4-AEEB-409D2F866F47}" = IWMSLayer
/// "{D43D9A73-FF6C-4A19-B36A-D7ECBE61962A}" = IWMSGroupLayer
/// "{8C19B114-1168-41A3-9E14-FC30CA5A4E9D}" = IWMSMapLayer
///</remarks>
public void LoopThroughLayersOfSpecificUID(ESRI.ArcGIS.Carto.IMap map, System.String layerCLSID)
{
  if(map == null || layerCLSID == null)
  {
    return;
  }
  ESRI.ArcGIS.esriSystem.IUID uid = new ESRI.ArcGIS.esriSystem.UIDClass();
  uid.Value = layerCLSID; // Example: "{E156D7E5-22AF-11D3-9F99-00C04F6BC78E}" = IGeoFeatureLayer
  try
  {
    ESRI.ArcGIS.Carto.IEnumLayer enumLayer = map.get_Layers(((ESRI.ArcGIS.esriSystem.UID)(uid)), true); // Explicit Cast
    enumLayer.Reset();
    ESRI.ArcGIS.Carto.ILayer layer = enumLayer.Next();
    while (!(layer == null))
    {
      // TODO - Implement your code here...
      layer = enumLayer.Next();
    }
  }
  catch (System.Exception ex)
  {
    //System.Windows.Forms.MessageBox.Show("No layers of type: " + uid.Value.ToString);
  }
}

[NeilClemmons · Accepted solution]

Yes.  While the terms themselves are not synonymous, in this case they all refer to the same identifier.