如何在Asp.Net MVC 4中validationHttpPostedFileBase属性的文件types？

我试图validation文件types的HttpPostedFileBase属性来检查文件的types，但我不能这样做，因为validation通过。 我怎么能这样做？

试

模型

 public class EmpresaModel{ [Required(ErrorMessage="Choose a file .JPG, .JPEG or .PNG file")] [ValidateFile(ErrorMessage = "Please select a .JPG, .JPEG or .PNG file")] public HttpPostedFileBase imagem { get; set; } } 

HTML

 <div class="form-group"> <label for="@Html.IdFor(model => model.imagem)" class="cols-sm-2 control-label">Escolha a imagem <img src="~/Imagens/required.png" height="6" width="6"></label> @Html.TextBoxFor(model => Model.imagem, new { Class = "form-control", placeholder = "Informe a imagem", type = "file" }) @Html.ValidationMessageFor(model => Model.imagem) </div> 

ValidateFileAttribute

 using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; using System.Drawing; using System.Drawing.Imaging; using System.Linq; using System.Web; //validate file if a valid image public class ValidateFileAttribute : RequiredAttribute{ public override bool IsValid(object value) { bool isValid = false; var file = value as HttpPostedFileBase; if (file == null || file.ContentLength > 1 * 1024 * 1024) { return isValid; } if (IsFileTypeValid(file)) { isValid = true; } return isValid; } private bool IsFileTypeValid(HttpPostedFileBase file) { bool isValid = false; try { using (var img = Image.FromStream(file.InputStream)) { if (IsOneOfValidFormats(img.RawFormat)) { isValid = true; } } } catch { //Image is invalid } return isValid; } private bool IsOneOfValidFormats(ImageFormat rawFormat) { List<ImageFormat> formats = getValidFormats(); foreach (ImageFormat format in formats) { if(rawFormat.Equals(format)) { return true; } } return false; } private List<ImageFormat> getValidFormats() { List<ImageFormat> formats = new List<ImageFormat>(); formats.Add(ImageFormat.Png); formats.Add(ImageFormat.Jpeg); //add types here return formats; } } 

Answer 1

因为你的属性inheritance自现有属性，所以需要在global.asax注册（参考这个例子），但是不要这样做。 您的validation代码不起作用，并且文件types属性不应该从RequiredAttributeinheritance – 它需要inheritanceValidationAttribute并且如果您想要客户端validation，那么还需要实现IClientValidatable 。 validation文件types的属性是（注意这个代码，如果属性是IEnumerable<HttpPostedFileBase>并validation集合中的每个文件）

 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)] public class FileTypeAttribute : ValidationAttribute, IClientValidatable { private const string _DefaultErrorMessage = "Only the following file types are allowed: {0}"; private IEnumerable<string> _ValidTypes { get; set; } public FileTypeAttribute(string validTypes) { _ValidTypes = validTypes.Split(',').Select(s => s.Trim().ToLower()); ErrorMessage = string.Format(_DefaultErrorMessage, string.Join(" or ", _ValidTypes)); } protected override ValidationResult IsValid(object value, ValidationContext validationContext) { IEnumerable<HttpPostedFileBase> files = value as IEnumerable<HttpPostedFileBase>; if (files != null) { foreach(HttpPostedFileBase file in files) { if (file != null && !_ValidTypes.Any(e => file.FileName.EndsWith(e))) { return new ValidationResult(ErrorMessageString); } } } return ValidationResult.Success; } public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) { var rule = new ModelClientValidationRule { ValidationType = "filetype", ErrorMessage = ErrorMessageString }; rule.ValidationParameters.Add("validtypes", string.Join(",", _ValidTypes)); yield return rule; } } 

它将被应用于一个物业

 [FileType("JPG,JPEG,PNG")] public IEnumerable<HttpPostedFileBase> Attachments { get; set; } 

并在视图中

 @Html.TextBoxFor(m => m.Attachments, new { type = "file", multiple = "multiple" }) @Html.ValidationMessageFor(m => m.Attachments) 

以下脚本需要客户端validation（与jquery.validate.js和jquery.validate.unobtrusive.js一起使用

 $.validator.unobtrusive.adapters.add('filetype', ['validtypes'], function (options) { options.rules['filetype'] = { validtypes: options.params.validtypes.split(',') }; options.messages['filetype'] = options.message; }); $.validator.addMethod("filetype", function (value, element, param) { for (var i = 0; i < element.files.length; i++) { var extension = getFileExtension(element.files[i].name); if ($.inArray(extension, param.validtypes) === -1) { return false; } } return true; }); function getFileExtension(fileName) { if (/[.]/.exec(fileName)) { return /[^.]+$/.exec(fileName)[0].toLowerCase(); } return null; } 

请注意，您的代码正试图validation文件的最大大小，这需要成为单独的validation属性。 有关validation最大允许大小的validation属性的示例，请参阅本文 。

另外，我推荐“ASP.NET MVC 3validation完整指南 – 第二部分”作为创build自定义validation属性的一个很好的指南