Microsoft.Office.Core 引用以及 Microsoft.Office.Core.MsoTriState 的问题

    using System;  
    using System.Collections.Generic;  
    using System.Linq;  
    using System.Text;  
    using PowerPoint = Microsoft.Office.Interop.PowerPoint;  
    using Microsoft.Office.Core;  
    using System.Runtime.InteropServices;  
    namespace ConsoleApplication1  
    {  
        public class Program  
        {  
            public static void Main(string[] args)  
            {  
                String fileName = "F://test.ppt";  
                Program.Parse(fileName);  
            }  
            public static void Parse(String fileName)  
            {  
                try  
                {  
                    PowerPoint.Application pa = new PowerPoint.ApplicationClass();  
                    PowerPoint.Presentation pp = pa.Presentations.Open(fileName,  
                                                                                                          Microsoft.Office.Core.MsoTriState.msoTrue,  
                                                                                                          Microsoft.Office.Core.MsoTriState.msoFalse,  
                                                                                                          Microsoft.Office.Core.MsoTriState.msoFalse);  
                    Console.WriteLine("Open Success");  
                    PowerPoint.TextFrame frame;  
                    String text;  
                    foreach (PowerPoint.Slide slide in pp.Slides)  
                    {                      
                        foreach (PowerPoint.Shape shape in slide.Shapes)  
                        {  
                              
                            if (shape.HasTextFrame == Microsoft.Office.Core.MsoTriState.msoTrue)  
                            {  
                                frame = shape.TextFrame;  
                                if (frame.HasText == Microsoft.Office.Core.MsoTriState.msoTrue)  
                                {  
                                      
                                    text = frame.TextRange.Text;  
                                    Console.WriteLine(text);  
                                }  
                            }  
                        }  
                    }  
                }  
                catch (Exception e)  
                {                  
                    Console.WriteLine(e.Message);  
                }  
            }  
        }  
    }