问asp.net mvc 3剃刀文件上传

EN

@if (TempData["imageUploadFailure"] != null)
{
    @* Here some jQuery popup for example *@
}

@using (Html.BeginForm("ImageUpload", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
{                  
    <legend>Add Image</legend>

    <label>Image</label>
    <input name="image" type="file" value=""/>
    <br/>

    <input type="submit" value="Send"/>
}

public ActionResult ImageUpload()
{
    return View();
}

[HttpPost]
public ActionResult ImageUpload(HttpPostedFileBase image)
{
    var result = ImageUtility.SaveImage("/Content/Images/", 1000000, "jpg,png", image, HttpContext.Server);

    if (!result.Success)
    {
        var builder = new StringBuilder();
        result.Errors.ForEach(e => builder.AppendLine(e));

        TempData.Add("imageUploadFailure", builder.ToString());
    }

    return RedirectToAction("ImageUpload");
}

public static class ImageUtility
{
    public static SaveImageResult SaveImage(string path, int maxSize, string allowedExtensions,  HttpPostedFileBase image, HttpServerUtilityBase server)
    {
        var result = new SaveImageResult { Success = false };

        if (image == null || image.ContentLength == 0)
        {
            result.Errors.Add("There was problem with sending image.");
            return result;
        }

        // Check image size
        if (image.ContentLength > maxSize)
            result.Errors.Add("Image is too big.");

        // Check image extension
        var extension = Path.GetExtension(image.FileName).Substring(1).ToLower();
        if (!allowedExtensions.Contains(extension))
            result.Errors.Add(string.Format("'{0}' format is not allowed.", extension));

        // If there are no errors save image
        if (!result.Errors.Any())
        {
            // Generate unique name for safety reasons
            var newName = Guid.NewGuid().ToString("N") + "." + extension;
            var serverPath = server.MapPath("~" + path + newName);
            image.SaveAs(serverPath);

            result.Success = true;
        }

        return result;
    }
}

public class SaveImageResult
{
    public bool Success { get; set; }
    public List<string> Errors { get; set; }

    public SaveImageResult()
    {
        Errors = new List<string>();
    }
}