Html helper for

Is there a HTMLHelper for file upload? Specifically, I am looking for a replace of

<input type="file"/> 

using ASP.NET MVC HTMLHelper.

Or, If I use

using (Html.BeginForm()) 

What is the HTML control for the file upload?

8 Answers

HTML Upload File ASP MVC 3.

Model: (Note that FileExtensionsAttribute is available in MvcFutures. It will validate file extensions client side and server side.)

public class ViewModel { [Required, Microsoft.Web.Mvc.FileExtensions(Extensions = "csv", ErrorMessage = "Specify a CSV file. (Comma-separated values)")] public HttpPostedFileBase File { get; set; } } 

HTML View:

@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { enctype = "multipart/form-data" })) { @Html.TextBoxFor(m => m.File, new { type = "file" }) @Html.ValidationMessageFor(m => m.File) } 

Controller action:

[HttpPost] public ActionResult Action(ViewModel model) { if (ModelState.IsValid) { // Use your file here using (MemoryStream memoryStream = new MemoryStream()) { model.File.InputStream.CopyTo(memoryStream); } } } 

You can also use:

@using (Html.BeginForm("Upload", "File", FormMethod.Post, new { enctype = "multipart/form-data" })) { <p> <input type="file" name="fileUpload" size="23" /> </p> <p> <input type="submit" value="Upload file" /></p> } 

I had this same question a while back and came across one of Scott Hanselman's posts:

Implementing HTTP File Upload with ASP.NET MVC including Tests and Mocks

Hope this helps.

Or you could do it properly:

In your HtmlHelper Extension class:

public static MvcHtmlString FileFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression) { return helper.FileFor(expression, null); } public static MvcHtmlString FileFor<TModel, TProperty>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes) { var builder = new TagBuilder("input"); var id = helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(ExpressionHelper.GetExpressionText(expression)); builder.GenerateId(id); builder.MergeAttribute("name", id); builder.MergeAttribute("type", "file"); builder.MergeAttributes(new RouteValueDictionary(htmlAttributes)); // Render tag return MvcHtmlString.Create(builder.ToString(TagRenderMode.SelfClosing)); } 

This line:

var id = helper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(ExpressionHelper.GetExpressionText(expression)); 

Generates an id unique to the model, you know in lists and stuff. model[0].Name etc.

Create the correct property in the model:

public HttpPostedFileBase NewFile { get; set; } 

Then you need to make sure your form will send files:

@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { enctype = "multipart/form-data" })) 

Then here's your helper:

@Html.FileFor(x => x.NewFile) 

Improved version of Paulius Zaliaduonis' answer:

In order to make the validation work properly I had to change the Model to:

public class ViewModel { public HttpPostedFileBase File { get; set; } [Required(ErrorMessage="A header image is required"), FileExtensions(ErrorMessage = "Please upload an image file.")] public string FileName { get { if (File != null) return File.FileName; else return String.Empty; } } } 

and the view to:

@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { enctype = "multipart/form-data" })) { @Html.TextBoxFor(m => m.File, new { type = "file" }) @Html.ValidationMessageFor(m => m.FileName) } 

This is required because what @Serj Sagan wrote about FileExtension attribute working only with strings.

To use BeginForm, here's the way to use it:

 using(Html.BeginForm("uploadfiles", "home", FormMethod.POST, new Dictionary<string, object>(){{"type", "file"}}) 

This also works:

Model:

public class ViewModel { public HttpPostedFileBase File{ get; set; } } 

View:

@using (Html.BeginForm("Action", "Controller", FormMethod.Post, new { enctype = "multipart/form-data" })) { @Html.TextBoxFor(m => m.File, new { type = "file" }) } 

Controller action:

[HttpPost] public ActionResult Action(ViewModel model) { if (ModelState.IsValid) { var postedFile = Request.Files["File"]; // now you can get and validate the file type: var isFileSupported= IsFileSupported(postedFile); } } public bool IsFileSupported(HttpPostedFileBase file) { var isSupported = false; switch (file.ContentType) { case ("image/gif"): isSupported = true; break; case ("image/jpeg"): isSupported = true; break; case ("image/png"): isSupported = true; break; case ("audio/mp3"): isSupported = true; break; case ("audio/wav"): isSupported = true; break; } return isSupported; } 

List of contentTypes

This is a little hacky I guess, but it results in the correct validation attributes etc being applied

@Html.Raw(Html.TextBoxFor(m => m.File).ToHtmlString().Replace("type=\"text\"", "type=\"file\""))