word转化为pdf

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.IO;
using System.Text;
using System.Threading;
using Microsoft.Office.Interop.Word;

namespace Word2Pdf
{
    class Program
    {
        public static Microsoft.Office.Interop.Word.Document wordDocument { get; set; }

        public void Main(string strFolder_f)
        {
            string strFolder_t = null;

            //CheckFolder(strFolder_t);
            string strPdfFile = null;
            DirectoryInfo TheFolder = new DirectoryInfo(strFolder_f);

            Microsoft.Office.Interop.Word.Application appWord = new Microsoft.Office.Interop.Word.Application();
            object paramMissing = Type.Missing;

            foreach (FileInfo NextFile in TheFolder.GetFiles())
            {
                strPdfFile = Path.ChangeExtension(strFolder_f "\\"   NextFile.Name, ".pdf");
                wordDocument = appWord.Documents.Open(NextFile.FullName);
                if (wordDocument != null)
                {
                    wordDocument.ExportAsFixedFormat(strPdfFile, WdExportFormat.wdExportFormatPDF);
                    wordDocument.Close(ref paramMissing, ref paramMissing, ref paramMissing);
                    wordDocument = null;
                }
            }

            if (appWord != null)
            {
                appWord.Quit(ref paramMissing, ref paramMissing, ref paramMissing);
                appWord = null;
            }

            //KillProcessByName("WINWORD");
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }

        static void CheckFolder(string strFolderPath)
        {
            if (Directory.Exists(strFolderPath))
            {
                Directory.Delete(strFolderPath, true);
                Directory.CreateDirectory(strFolderPath);
            }
            else
            {
                Directory.CreateDirectory(strFolderPath);
            }
        }

        static void KillProcessByName(string name)
        {
            Process[] ps = Process.GetProcessesByName(name);
            foreach (Process p in ps)
            {
                if (p.ProcessName == name)
                    p.Kill();
            }
        }
    }
}