c# 判断文件是否已使用

            string path = Server.MapPath(" PDFs");
            bool tfOpenTemp= IsFileInUse(path + " /Doc1.pdf ");
            if (!tfOpenTemp)
            {

            }
            else
            {
                Alert("打印模板已调用，请关闭后进行此操作！");
            }

       #region 提示信息
        //提示信息 using System.Web.UI;
        public void Alert(string str_Message)
        {
            ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
            scriptManager.RegisterStartupScript(typeof(string), "", "alert('" + str_Message + "');", true);
        }
        public void Alert(string str_Message, string redirect)
        {
            ClientScriptManager scriptManager = ((Page)System.Web.HttpContext.Current.Handler).ClientScript;
            scriptManager.RegisterStartupScript(typeof(string), "", "alert('" + str_Message + "');self.location='" + redirect + "'", true);
        }
        #endregion

        #region 判断文件是否已使用
        public static bool IsFileInUse(string fileName)
        {
            bool inUse = true;
            if (File.Exists(fileName))
            {
                FileStream fs = null;
                try
                {
                    fs = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None);
                    inUse = false;
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message.ToString());
                }
                finally
                {
                    if (fs != null)
                    {
                        fs.Close();
                    }
                }
                return inUse;           //true表示正在使用,false没有使用
            }
            else
            {
                return false;           //文件不存在则一定没有被使用
            }
        }
        #endregion