Question

我在我的MVC应用程序中实现了一个图像上传选项但是我一直收到以下错误：找不到类型或命名空间名称'FileSizeAttribute'。

从下面的代码中我可以看到，我正在实现cusom属性来确定允许的文件大小和类型。

public class UploadImageModel
    {
        [FileSize(10240)]
        [FileTypes("jpg,jpeg,png")]
        public HttpPostedFileBase File { get; set; }
    }

我在ProfileController.cs中定义了这些属性，你可以在这里看到。

public class FileSizeAttribute : ValidationAttribute
        {
            private readonly int _maxSize;

            public FileSizeAttribute(int maxSize)
            {
                _maxSize = maxSize;
            }

            public override bool IsValid(object value)
            {
                if (value == null) return true;

                return _maxSize > (value as HttpPostedFile).ContentLength;
            }
            public override string FormatErrorMessage(string name)
            {
                return string.Format("The image size should not exceed {0}", _maxSize);
            }
        }

        public class FileTypesAttribute : ValidateInputAttribute
        {
            private readonly List<string> _types;

            public FileTypesAttribute(string types)
            {
                _types = types.Split(',').ToList();
            }

            public override bool IsValid(object value)
            {
                if (value == null) return true;

                var fileExt = System.IO.Path.GetExtension((value as HttpPostedFile).FileName).Substring(1);
                return _types.Contains(fileExt, StringComparer.OrdinalIgnoreCase);
            }

            public override string FormatErrorMessage(string name)
            {
                return string.Format("Invalid file type. Only the following types {0} are supported.",
                    String.Join(", ", _types));
            }
        }
        [HttpPost]
        public ActionResult PhotoUpload(UploadImageModel imageModel)
        {
            string path = @"D:\Temp\";

            if (ModelState.IsValid)
            {
                if (imageModel != null && imageModel.File != null)
                    image.SaveAs(path + imageModel.File.FileName);

                return RedirectToAction("Profile");
            }

            return View();
        }

我应该提一下，我正在调整此article的代码，因为我是MVC的新手并且正在学习绳索。也就是说，我需要在头文件中包含一个using子句，引用我的Controller，还是我缺少的语法问题？在此先感谢您的帮助。

Answer 1

让我们假设您至少将这些属性移到一个组合文件中，称之为ExtensionAttributes.cs。在该文件中，您将拥有类似

的内容

namespace artisan.Attributes
{
    public class FileSizeAttribute : ValidationAttribute
    {
        private readonly int _maxSize;

        public FileSizeAttribute(int maxSize)
        {
            _maxSize = maxSize;
        }

        public override bool IsValid(object value)
        {
            if (value == null) return true;

            return _maxSize > (value as HttpPostedFile).ContentLength;
        }
        public override string FormatErrorMessage(string name)
        {
            return string.Format("The image size should not exceed {0}", _maxSize);
        }
    }

    public class FileTypesAttribute : ValidateInputAttribute
    {
        private readonly List<string> _types;

        public FileTypesAttribute(string types)
        {
            _types = types.Split(',').ToList();
        }

        public override bool IsValid(object value)
        {
            if (value == null) return true;

            var fileExt = System.IO.Path.GetExtension((value as HttpPostedFile).FileName).Substring(1);
            return _types.Contains(fileExt, StringComparer.OrdinalIgnoreCase);
        }

        public override string FormatErrorMessage(string name)
        {
            return string.Format("Invalid file type. Only the following types {0} are supported.",
                String.Join(", ", _types));
        }
    }
}

然后，要在模型上使用该属性，您可以执行类似

的操作

using artisan.Attributes;

public class UploadImageModel
{
    [FileSize(10240)]
    [FileTypes("jpg,jpeg,png")]
    public HttpPostedFileBase File { get; set; }
}

否则，按原样，您需要向模型类添加artisan.Controllers，但是（给定默认项目模板）可能会导致一些循环引用。

ASP.NET MVC 5自定义属性错误

1 个答案: