public void OnConnection(object application, ext_ConnectMode 
  connectMode, object addInInst, ref Array custom)
{
    _applicationObject = (DTE2)application;
    _addInInstance = (AddIn)addInInst;
    macroTest(_applicationObject);
}

public void macroTest(DTE2 dte)
{
    try
    {
        Macros objMac = dte.Macros;
        // Determine if a macro is recording. If it is, 
        // add a line of code to it and then let it resume 
        // recording.
        if (objMac.IsRecording == true)
        {
            objMac.EmitMacroCode("MsgBox(\"This was added by 
              code.\")");
        }
        else
        {
            System.Windows.Forms.MessageBox.Show("Macro is not 
              recording.");
        }
    }
    catch (Exception ex)
    {
        System.Windows.Forms.MessageBox.Show(ex.Message);
    }
}

Public Module RecordingModule
    Sub TemporaryMacro()
        DTE.ItemOperations.NewFile("General\Text File")
    End Sub
End Module

Public Module RecordingModule
    Sub TemporaryMacro()
        DTE.ItemOperations.NewFile("General\Text File")
        MsgBox("This line was added by code.")
    End Sub
End Module