打开Word文件并显示在RichtTextBox上

private void btn_word_Click(object sender, EventArgs e)        {    //调用对话框打开的word文件，RTFW文件，           OpenFileDialog opd = new OpenFileDialog();    //文件路径的初始磁盘位置            opd.InitialDirectory = "D:\\\\";    //选择打开文件的类型            opd.Filter = "Word文档(*.doc)|*.doc|文本文档(*.txt)|*.txt|RTF文档(*.rtf)|*.rtf|所有文档(*.*)|*.*";    //默认选择文件类型为第一个word(*.doc)            opd.FilterIndex = 1;    //判断文件的是否被打开并且不为空            if(opd.ShowDialog() == DialogResult.OK && opd.FileName.Length > 0)            {//实例化一个word                word = new Word.ApplicationClass();                object missing = System.Reflection.Missing.Value;                object FileName = opd.FileName;//只读属性为false                object readOnly = false;                object isVisible = true;                object index = 0;                try                {    //打开指定文件                    doc = word.Documents.Open(ref FileName, ref missing, ref readOnly,                        ref missing, ref missing, ref missing, ref missing, ref missing,                        ref missing, ref missing, ref missing, ref isVisible, ref missing,                        ref missing, ref missing, ref missing);    //全选word文档中的数据                    doc.ActiveWindow.Selection.WholeStory();            //复制数据到剪切板                    doc.ActiveWindow.Selection.Copy();    //RichTextBox粘贴数据                    this.richTextBox1.Paste();                }                finally                {                    if(doc != null)                    {//关闭文件                        doc.Close(ref missing, ref missing, ref missing);                        doc = null;                    }                    if(word != null)                    {                        word.Quit(ref missing,ref missing,ref missing);                        word = null;                    }                }            }        }