C# 操作Word批量替换

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;

namespace TextReplace
{
    public class WordOperate : IDisposable
    {
        private Microsoft.Office.Interop.Word._Application _app;
        private Microsoft.Office.Interop.Word._Document _doc;
        object _nullobj = System.Reflection.Missing.Value;

        /// <summary>
        /// 关闭Word进程
        /// </summary>
        public void KillWinword()
        {
            var p = Process.GetProcessesByName("WINWORD");
            if (p.Any()) p[0].Kill();
        }

        /// <summary>
        /// 打开word文档
        /// </summary>
        /// <param name="filePath"></param>
        public void Open(string filePath)
        {

            _app = new Microsoft.Office.Interop.Word.ApplicationClass();
            object file = filePath;
            _doc = _app.Documents.Open(
                 ref file, ref _nullobj, ref _nullobj,
                 ref _nullobj, ref _nullobj, ref _nullobj,
                 ref _nullobj, ref _nullobj, ref _nullobj,
                 ref _nullobj, ref _nullobj, ref _nullobj,
                 ref _nullobj, ref _nullobj, ref _nullobj, ref _nullobj);
        }


        /// <summary>
        /// 替换word中的文字
        /// </summary>
        /// <param name="strOld">查找的文字</param>
        /// <param name="strNew">替换的文字</param>
        public void Replace(string strOld, string strNew)
        {
            _app.Selection.Find.ClearFormatting();
            _app.Selection.Find.Replacement.ClearFormatting();
            _app.Selection.Find.Text = strOld;
            _app.Selection.Find.Replacement.Text = strNew;

            object objReplace = Microsoft.Office.Interop.Word.WdReplace.wdReplaceAll;
            _app.Selection.Find.Execute(ref _nullobj, ref _nullobj, ref _nullobj,
                                       ref _nullobj, ref _nullobj, ref _nullobj,
                                       ref _nullobj, ref _nullobj, ref _nullobj,
                                       ref _nullobj, ref objReplace, ref _nullobj,
                                       ref _nullobj, ref _nullobj, ref _nullobj);
        }

        /// <summary>
        /// 保存
        /// </summary>
        public void Save()
        {
            _doc.Save();
        }

        /// <summary>
        /// 退出
        /// </summary>
        public void Dispose()
        {
            _doc.Close(ref _nullobj, ref _nullobj, ref _nullobj);
            _app.Quit(ref _nullobj, ref _nullobj, ref _nullobj);
        }
    }
}