Add Layer File to ActiveView Snippet

///<summary>Add a layer file (.lyr) into the active view when the path (on disk or network) is specified.</summary>
///      
///<param name="activeView">An IActiveview interface</param>
///<param name="layerPathFile">A System.String that is the path\filename of a layer file. Example: "C:\temp\mylayer.lyr".</param>
///      
///<remarks></remarks>
public void AddLayerToActiveView(ESRI.ArcGIS.Carto.IActiveView activeView, System.String layerPathFile)
{

  if (activeView == null || layerPathFile == null || !layerPathFile.EndsWith(".lyr"))
  {
    return;
  }
  
  // Create a new GxLayer
  ESRI.ArcGIS.Catalog.IGxLayer gxLayer = new ESRI.ArcGIS.Catalog.GxLayerClass();

  ESRI.ArcGIS.Catalog.IGxFile gxFile = (ESRI.ArcGIS.Catalog.IGxFile)gxLayer; //Explicit Cast

  // Set the path for where the layerfile is located on disk
  gxFile.Path = layerPathFile;

  // Test if we have a valid layer and add it to the map
  if (!(gxLayer.Layer == null))
  {
    ESRI.ArcGIS.Carto.IMap map = activeView.FocusMap;
    map.AddLayer(gxLayer.Layer);
  }
}

'''<summary>Add a layer file (.lyr) into the active view when the path (on disk or network) is specified.</summary>
'''      
'''<param name="activeView">An IActiveview interface</param>
'''<param name="layerPathFile">A System.String that is the path\filename of a layer file. Example: "C:\temp\mylayer.lyr".</param>
'''      
'''<remarks></remarks>
Public Sub AddLayerToActiveView(ByVal activeView As ESRI.ArcGIS.Carto.IActiveView, ByVal layerPathFile As System.String)

  If activeView Is Nothing OrElse layerPathFile Is Nothing OrElse (Not layerPathFile.EndsWith(".lyr")) Then

  	Return

  End If

  ' Create a new GxLayer
  Dim gxLayer As ESRI.ArcGIS.Catalog.IGxLayer = New ESRI.ArcGIS.Catalog.GxLayerClass

  Dim gxFile As ESRI.ArcGIS.Catalog.IGxFile = CType(gxLayer, ESRI.ArcGIS.Catalog.IGxFile) 'Explicit Cast

  ' Set the path for where the layerfile is located on disk
  gxFile.Path = layerPathFile

  ' Test if we have a valid layer and add it to the map
  If Not(gxLayer.Layer Is Nothing) Then

	  Dim map As ESRI.ArcGIS.Carto.IMap = activeView.FocusMap
	  map.AddLayer(gxLayer.Layer)

  End If

End Sub