C#工具:ASP.NET MVC單例模式(懶漢)實現文件上傳

1.SingletonConfigRead幫助類

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace WebApplication2.Models
{
    public class SingletonConfigRead
    {
        public static readonly string Config = "";
        //封閉無參構造函數，防止外部實例化調用
        private SingletonConfigRead() { }
        //建立一個對象爲屬性
        private static SingletonConfigRead single;
        /// <summary>
        /// 外部經過調用該方法獲得對象（線程安全的懶漢單利模式）
        /// </summary>
        /// <returns></returns>
        public static SingletonConfigRead GetInstns()
        {

            if (single == null)
            {
                lock (Config)
                {
                    single = new SingletonConfigRead();
                }

            }

            return single;
        }

        public string UploadFile(HttpPostedFileBase txtFile)
        {

            if (txtFile != null)
            {
                string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory + "Content\\", txtFile.FileName);
                txtFile.SaveAs(path);
                using (FileStream fs = new FileStream(path, FileMode.Open))
                {
                    StreamReader sr = new StreamReader(fs, System.Text.Encoding.Default);
                    return sr.ReadToEnd();

                }

            }
            return null;
        }
    }
}

2.前臺代碼

  <div>
        @using (Html.BeginForm("Index", "File", FormMethod.Post, new { enctype = "multipart/form-data" }))
        {
            @Html.TextBox("txtFile", "", new { @type = "file" })
            <input id="Submit1" type="submit" value="上傳" />
            <input id="Submit1" type="submit" value="讀取文件" />
            <br />
            @:上傳文件是：@ViewBag.fileName &nbsp;&nbsp;&nbsp;&nbsp;
            @:文件內容是：@ViewBag.fileContent
        }
    </div>

3.後臺代碼

  // GET: File
        public ActionResult Index()
        {
            return View();
        }
        [HttpPost]
        public ActionResult Index(HttpPostedFileBase txtFile)
        {
          
            if (txtFile != null)
            {
                SingletonConfigRead s = SingletonConfigRead.GetInstns();
                ViewBag.fileContent = s.UploadFile(txtFile);
                ViewBag.fileName = txtFile.FileName;
               
            }
           
            return View();
        }