在 MVC 4 中上传/显示图像

问题描述：

有人知道有关如何使用实体框架从数据库上传/显示图像的分步教程吗?我已经检查了代码片段，但我仍然不清楚它是如何工作的.我没有代码，因为除了编写上传表单之外，我迷路了.非常感谢任何(我的意思是任何)帮助.

Anyone know of any step by step tutorials on how to upload/display images from a database using Entity Framework? I've checked out code snippets, but I'm still not clear on how it works. I have no code, because aside from writing an upload form, I'm lost. Any (and I mean any) help is greatly appreciated.

顺便说一句，为什么没有任何书籍涉及这个主题?我有 Pro ASP.NET MVC 4 和 Professional MVC4，但他们没有提及.

On a sidenote, why don't any books cover this topic? I have both Pro ASP.NET MVC 4 and Professional MVC4, and they make no mention of it.

答

看看下面的

@using (Html.BeginForm("FileUpload", "Home", FormMethod.Post, 
                            new { enctype = "multipart/form-data" }))
{  
    <label for="file">Upload Image:</label> 
    <input type="file" name="file" id="file" style="width: 100%;" /> 
    <input type="submit" value="Upload" class="submit" /> 
}

你的控制器应该有接受 HttpPostedFileBase 的 action 方法；

your controller should have action method which would accept HttpPostedFileBase;

 public ActionResult FileUpload(HttpPostedFileBase file)
    {
        if (file != null)
        {
            string pic = System.IO.Path.GetFileName(file.FileName);
            string path = System.IO.Path.Combine(
                                   Server.MapPath("~/images/profile"), pic); 
            // file is uploaded
            file.SaveAs(path);

            // save the image path path to the database or you can send image 
            // directly to database
            // in-case if you want to store byte[] ie. for DB
            using (MemoryStream ms = new MemoryStream()) 
            {
                 file.InputStream.CopyTo(ms);
                 byte[] array = ms.GetBuffer();
            }

        }
        // after successfully uploading redirect the user
        return RedirectToAction("actionname", "controller name");
    }

更新 1

如果您想使用 jQuery 异步上传文件，请尝试这篇文章.

In case you want to upload files using jQuery with asynchornously, then try this article.

处理服务器端(用于多次上传)的代码是;

the code to handle the server side (for multiple upload) is;

 try
    {
        HttpFileCollection hfc = HttpContext.Current.Request.Files;
        string path = "/content/files/contact/";

        for (int i = 0; i < hfc.Count; i++)
        {
            HttpPostedFile hpf = hfc[i];
            if (hpf.ContentLength > 0)
            {
                string fileName = "";
                if (Request.Browser.Browser == "IE")
                {
                    fileName = Path.GetFileName(hpf.FileName);
                }
                else
                {
                    fileName = hpf.FileName;
                }
                string fullPathWithFileName = path + fileName;
                hpf.SaveAs(Server.MapPath(fullPathWithFileName));
            }
        }

    }
    catch (Exception ex)
    {
        throw ex;
    }

此控件还返回图像名称(在 javascript 回调中)，然后您可以使用它在 DOM 中显示图像.

this control also return image name (in a javascript call back) which then you can use it to display image in the DOM.

或者，您可以尝试异步文件上传MVC 4.

Alternatively, you can try Async File Uploads in MVC 4.

在 MVC 4 中上传/显示图像

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