public void wordchangetohtml(string sourcepath, string htmlpath)
    {
        try
        {
            Word.ApplicationClass word = new Word.ApplicationClass();
            Type wordType = word.GetType();
            Word.Documents docs = word.Documents;
            // 打开文件
            Type docsType = docs.GetType();
            object fileName = sourcepath;
            Word.Document doc = (Word.Document)docsType.InvokeMember("Open",
            System.Reflection.BindingFlags.InvokeMethod, null, docs, new Object[] { fileName, true, true });

            // 转换格式，另存为
            Type docType = doc.GetType();
            object saveFileName = htmlpath;
            ///wdFormatUnicodeText
            docType.InvokeMember("SaveAs", System.Reflection.BindingFlags.InvokeMethod, null, doc, new object[] { saveFileName, Word.WdSaveFormat.wdFormatHTML });
            // 退出 Word
            wordType.InvokeMember("Quit", System.Reflection.BindingFlags.InvokeMethod, null, word, null);
        }
        catch (Exception EX)
        {

            throw EX;
        }
    }