效果图：

代码如下：
引用：js，css

<script src="~/Scripts/bootstrap-fileupload.min.js"></script>
<script src="~/js/FileSize.js"></script>
<link href="~/Content/bootstrap-fileupload.min.css" rel="stylesheet" />

附件下载请点击这里

View里的代码：

<div class="row">
    @using (Html.BeginForm("Create", "RotatePic", FormMethod.Post, new { id = "formid", enctype = "multipart/form-data" }))
    {
        @Html.AntiForgeryToken()

        <div class="form-horizontal" style="margin-top:20px">
            <div class="form-group">
                <label class="col-md-2 col-sm-2 control-label">轮播图</label>
                <div class="col-md-3 col-sm-4">
                    <div class="fileupload fileupload-new" data-provides="fileupload">
                        <div class="fileupload-new thumbnail" style="width: 200px; height: 150px;">
                            ![](http://www.placehold.it/200x150/EFEFEF/AAAAAA&text=no+image)
                        </div>
                        <div class="fileupload-preview fileupload-exists thumbnail" style="max-width: 200px; max-height: 150px; line-height: 20px;"></div>
                        <div>
                            <span class="btn btn-default btn-file">
                                <span class="fileupload-new"><i class="fa fa-paper-clip"></i> Select image</span>
                                <span class="fileupload-exists"><i class="fa fa-undo"></i> Change</span>
                                <input name="file" id="file" type="file" accept=".png,.jpg" class="default" />
                            </span>
                            <a href="#" class="btn btn-danger fileupload-exists" data-dismiss="fileupload"><i class="fa fa-trash"></i> Remove</a>
                        </div>
                    </div>
                </div>
            </div>
            <div class="form-group">
                <div class="col-md-offset-2 col-lg-10">
                    <input type="submit" value="保存" class="btn btn-primary" onclick="Check()" />
                    <input type="button" class="btn btn-default" onclick="window.history.go(-1)" value="返回" />
                </div>
            </div>

        </div>
    }
</div>

@section scripts{
    <script src="~/js/FileSize.js"></script>
}

Controller里的代码：

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Create(RotatePic rotatePic, HttpPostedFileBase file)
        {
            if (ModelState.IsValid)
            {
                //轮播图
                if (file != null && file.FileName != "")
                {
                    if (System.IO.Path.GetExtension(file.FileName).ToLower() == ".jpg" || System.IO.Path.GetExtension(file.FileName).ToLower() == ".png")
                    {
                        rotatePic.BannerPic = Updatefile(file);
                    }
                    else
                    {
                        ViewBag.msg = "<script>alert('正面上传的图片格式不正确！')</script>";
                        return View();
                    }
                }

                if (rotatePic != null)
                {
                    rotatePic.CreateTime = DateTime.Now;
                    db.RotatePic.Add(rotatePic);
                    db.SaveChanges();
                }
                return RedirectToAction("Index");
            }
            return View();
        }
//图片处理，直接复制代码
 public string Updatefile(HttpPostedFileBase file)
        {
            string path = "";
            if (file != null)
            {
                var fileName = Path.Combine(Request.MapPath("~/Upload"), Path.GetFileName(file.FileName));
                string ext = System.IO.Path.GetExtension(file.FileName);
                if (!Directory.Exists(fileName))
                {
                    string n = Guid.NewGuid().ToString();
                    string newname = n + ext;
                    fileName = Path.Combine(Request.MapPath("~/Upload"), Path.GetFileName(newname));

                    if (ext.ToLower() == ".jpg")
                    {
                        Common.ImageHelper.CompressionJpgImage(file.InputStream, fileName);
                    }
                    else
                    {
                        Common.ImageHelper.CompressionPngImage(file.InputStream, fileName);
                    }
                    path = "../Upload/" + Path.GetFileName(newname);
                }
                else
                {
                    if (ext.ToLower() == ".jpg")
                    {
                        Common.ImageHelper.CompressionJpgImage(file.InputStream, fileName);
                    }
                    else
                    {
                        Common.ImageHelper.CompressionPngImage(file.InputStream, fileName);
                    }
                    path = "../Upload/" + Path.GetFileName(file.FileName);
                }
            }
            return path;
        }