Question

我对MVC4编码很新。以前一直在SharePoint中编程。

我遇到的问题是我想将图像保存到特定文件夹（比如App_Data），并将图像的URL保存到数据库中的字符串。如果有人能帮助我解决这个问题会很棒。

我现在得到的代码是。

模型＆gt; ImageUpload.cs

public class ImageUpload

{
    public int ID { get; set; }
    public string Title { get; set; } 
    public string Url { get; set; }
}

public class ImageUploadDBContext : DbContext
{
    public DbSet<ImageUpload> ImageUploads { get; set; }
}

控制器＆gt; ImageUploadController.cs

[HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Create(ImageUpload imageupload)
    {
        if (ModelState.IsValid)
        {
            db.ImageUploads.Add(imageupload);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

        return View(imageupload);
    }

[HttpPost]
    public ActionResult Upload(HttpPostedFileBase[] files)
    {
        foreach (HttpPostedFileBase file in files)
        {
            string picture = Path.GetFileName(file.FileName);
            string path = Path.Combine(Server.MapPath("~/App_Data"), picture);
            string[] paths = path.Split('.');
            string time = DateTime.UtcNow.ToString();
            time = time.Replace(" ", "-");
            time = time.Replace(":", "-"); 
            file.SaveAs(paths[0] + "-" + time + ".jpg");
        }
        ViewBag.Message = "File(s) uploaded successfully";
        return RedirectToAction("Index");
    }

查看＆gt; ImageUpload＆gt; Index.cshtml

@{
ViewBag.Title = "Index";
}

<h2>Index</h2>

<p>
    @Html.ActionLink("Create New", "Create")
</p>
<table>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.Title)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.Url)
        </th>
        <th>
            Preview
        </th>
        <th></th>
    </tr>

    @foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.Title)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.Url)
            </td>
            <td>
                <img border="0" src="@Html.DisplayFor(modelItem => item.Url)" alt="@Html.DisplayFor(modelItem => item.Title)">
            </td>
            <td>
                @Html.ActionLink("Edit", "Edit", new { id=item.ID }) |
                @Html.ActionLink("Details", "Details", new { id=item.ID }) |
                @Html.ActionLink("Delete", "Delete", new { id=item.ID })
            </td>
        </tr>    
    }
</table>

查看＆gt; ImageUpload＆gt; Create.cshtml

@{
    ViewBag.Title = "Create";
}

<h2>Create</h2>

@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>ImageUpload</legend>

            @using (Html.BeginForm())
            {
                    <div class="editor-label">
                        <b>@Html.LabelFor(Model => Model.Title)</b>
                    </div>
                    <div class="editor-field">
                        @Html.EditorFor(Model => Model.Title)
                        @Html.ValidationMessageFor(Model => Model.Title)
                    </div>
                    <div class="editor-label">
                        <b>@Html.LabelFor(Model => Model.Url)</b>
                    </div>
                    <div>
                        @Html.EditorFor(Model => Model.Url)
                        <input type="file" name="files" value="" multiple="multiple"/>
                    </div>
                    <div>
                        <input type="submit" value="Submit" />
                    </div>
            }


    </fieldset>
}

<div>
    @Html.ActionLink("Back to List", "Index")
</div>

@section Scripts {
    @Scripts.Render("~/bundles/jqueryval")
}

Answer 1

对于文件上传，您可以使用此代码。保存到文件夹的图像和存储到数据库的文件名：

在控制器中：

[HttpPost]
public ActionResult Create(EventModel eventmodel, HttpPostedFileBase file)
{ 
   if (ModelState.IsValid)
   {
      var filename = Path.GetFileName(file.FileName);
      var path = Path.Combine(Server.MapPath("~/Uploads/Photo/"), filename);
      file.SaveAs(path);
      tyre.Url = filename;

      _db.EventModels.AddObject(eventmodel);
      _db.SaveChanges();
      return RedirectToAction("Index");
   }
   return View(eventmodel);
}

观看：

<div>
   Image
   <input type="file" name="file" id="file" />
   @Html.HiddenFor( model => model.ImageUrl)
   @Html.ValidationMessageFor( model => model.Url )
</div>

Answer 2

将两种方法合并为一种方法逻辑，代码应该是这样的：

[HttpPost]
[ValidateAntiForgeryToken]
    public ActionResult Upload(HttpPostedFileBase[] files)
    {
        // try to save the file
        foreach (HttpPostedFileBase file in files)
        {
            string picture = Path.GetFileName(file.FileName);
            string path = Path.Combine(Server.MapPath("~/App_Data"), picture);
            string[] paths = path.Split('.');
            string time = DateTime.UtcNow.ToString();
            time = time.Replace(" ", "-");
            time = time.Replace(":", "-"); 
            file.SaveAs(paths[0] + "-" + time + ".jpg");
        }

        // try to save the new file name to db now.
        try
        {
            db.ImageUploads.Add(paths[0] + time + ".jpg");
            db.SaveChanges();
        }
        catch(Exception ex)
        {
             ..........
        }

        ViewBag.Message = "File(s) uploaded successfully";
        return RedirectToAction("Index");
    }

Answer 3

在您的控制器操作中，您需要执行HTTP请求以从远程服务器获取映像：

public ActionResult Thumb(int id)
{
    using (var client = new WebClient())
    {
        byte[] image = client.DownloadData("http://cdn.foo.com/myimage.jpg");
        return File(image, "image/jpg");
    }
}

然后：

<img src="@Url.Action("Thumb")" alt="" />

显然现在图像被下载了两次。一旦从CDN进入控制器，一次从客户端进入。这完全违背了此控制器操作的目的，您可以直接引用CDN中的图像：

<img src="http://cdn.foo.com/myimage.jpg" alt="" />

这显然假设客户端可以访问CDN。

当然，如果您的控制器操作不仅仅是从CDN获取图像并将其流式传输到客户端，例如从CDN获取图像并调整其大小，那么您绝对应该采用第一种方法。

来自：stackoverflow

MVC4 C＃ - 想要将图像保存到文件夹并将URL保存在数据库中

3 个答案: