Rhino maintains layers on a CRhinoLayerTable object that is located on the active CRhinoDoc object. The CRhinoLayerTable class has numerous methods for adding, querying, modifying, and deleting layers. See rhinoSdkLayer.h for more information on the CRhinoLayerTable class.

C++

  CRhinoCommand::result CCommandTest::RunCommand( const CRhinoCommandContext& context )
  {
    // Get reference to the document's layer table
    CRhinoLayerTable& layer_table = context.m_doc.m_layer_table;
    // Cook up an unused layer name
    ON_wString unused_name;
    layer_table.GetUnusedLayerName( unused_name );


    // Prompt the user to enter a layer name
    CRhinoGetString gs;
    gs.SetCommandPrompt( L"Name of layer to add" );
    gs.SetDefaultString( unused_name );
    gs.AcceptNothing( TRUE );
    gs.GetString();
    if( gs.CommandResult() != CRhinoCommand::success )
      return gs.CommandResult();


    // Was a layer named entered?
    ON_wString layer_name = gs.String();
    layer_name.TrimLeftAndRight();
    if( layer_name.IsEmpty() )
    {
      RhinoApp().Print( L"Layer name cannot be blank.\n" );
      return CRhinoCommand::cancel;
    }


    // Is the layer name valid?
    if( !RhinoIsValidName(layer_name) )
    {
      RhinoApp().Print( L"\"%s\" is not a valid layer name.\n", layer_name );
      return CRhinoCommand::cancel;
    }


    // Does a layer with the same name already exist?
    int layer_index = layer_table.FindLayer( layer_name );
    if( layer_index >= 0 )
    {
      RhinoApp().Print( L"A layer with the name \"%s\" already exists.\n", layer_name );
      return CRhinoCommand::cancel;
    }


    // Create a new layer
    ON_Layer layer;
    layer.SetLayerName( layer_name );
    // Add the layer to the layer table
    layer_index = layer_table.AddLayer( layer );
    if( layer_index < 0 )
    {
      RhinoApp().Print( L"Unable to add \"%s\" layer.\n", layer_name );
      return CRhinoCommand::failure;
    }
    return CRhinoCommand::success;
  }

VB.NET (Rhino 4)

  Public Overrides Function RunCommand(ByVal context As IRhinoCommandContext) _
    As IRhinoCommand.result


    ' Get a reference to the layer table
    Dim layer_table As MRhinoLayerTable = context.m_doc.m_layer_table
    ' Cook up an unused layer name
    Dim unused_name As String = ""
    layer_table.GetUnusedLayerName(unused_name)


    ' Prompt the user to enter a layer name
    Dim gs As New MRhinoGetString()
    gs.SetCommandPrompt("Name of layer to add")
    gs.SetDefaultString(unused_name)
    gs.AcceptNothing(True)
    gs.GetString()
    If (gs.CommandResult() <> IRhinoCommand.result.success) Then
      Return gs.CommandResult()
    End If


    ' Was a layer named entered?
    Dim layer_name As String = gs.String()
    layer_name = layer_name.Trim()
    If (String.IsNullOrEmpty(layer_name)) Then
      RhUtil.RhinoApp().Print("Layer name cannot be blank."+vbrclf)
      Return IRhinoCommand.result.cancel
    End If


    ' Is the layer name valid?
    If (RhUtil.RhinoIsValidName(layer_name) = 0) Then
      RhUtil.RhinoApp().Print(layer_name + " is not a valid layer name."+vbcrlf)
      Return IRhinoCommand.result.cancel
    End If


    ' Does a layer with the same name already exist?
    Dim layer_index As Integer = layer_table.FindLayer(layer_name)
    If (layer_index >= 0) Then
      Dim msg As String = "A layer with the name "+layer_name+" already exists."+ vbcrlf
      RhUtil.RhinoApp().Print(msg)
      Return IRhinoCommand.result.cancel
    End If


    ' Create a new layer
    Dim layer As New OnLayer()
    layer.SetLayerName(layer_name)
    ' Add the layer to the layer table
    layer_index = layer_table.AddLayer(layer)
    If (layer_index < 0) Then
      RhUtil.RhinoApp().Print(String.Format("Unable to add {0} layer."+vbcrlf, layer_name))
      Return IRhinoCommand.result.failure
    End If
    Return IRhinoCommand.result.success
  End Function

C# (Rhino 4)

  public override IRhinoCommand.result RunCommand(IRhinoCommandContext context)
  {
    // Get a reference to the layer table
    MRhinoLayerTable layer_table = context.m_doc.m_layer_table;
    // Cook up an unused layer name
    string unused_name = "";
    layer_table.GetUnusedLayerName(ref unused_name);


    // Prompt the user to enter a layer name
    MRhinoGetString gs = new MRhinoGetString();
    gs.SetCommandPrompt("Name of layer to add");
    gs.SetDefaultString(unused_name);
    gs.AcceptNothing(true);
    gs.GetString();
    if( gs.CommandResult() != IRhinoCommand.result.success )
      return gs.CommandResult();


    // Was a layer named entered?
    string layer_name = gs.String();
    layer_name = layer_name.Trim();
    if (string.IsNullOrEmpty(layer_name))
    {
      RhUtil.RhinoApp().Print("Layer name cannot be blank.\n");
      return IRhinoCommand.result.cancel;
    }


    // Is the layer name valid?
    if (RhUtil.RhinoIsValidName(layer_name) == 0)
    {
      RhUtil.RhinoApp().Print(layer_name + " is not a valid layer name.\n");
      return IRhinoCommand.result.cancel;
    }


    // Does a layer with the same name already exist?
    int layer_index = layer_table.FindLayer(layer_name);
    if( layer_index >= 0 )
    {
      string msg = string.Format("A layer with the name {0} already exists.\n", layer_name);
      RhUtil.RhinoApp().Print( msg );
      return IRhinoCommand.result.cancel;
    }


    // Create a new layer
    OnLayer layer = new OnLayer();
    layer.SetLayerName(layer_name);
    // Add the layer to the layer table
    layer_index = layer_table.AddLayer(layer);
    if( layer_index < 0 )
    {
      RhUtil.RhinoApp().Print( string.Format("Unable to add {0} layer.\n", layer_name ));
      return IRhinoCommand.result.failure;
    }
    return IRhinoCommand.result.success;
  }