Html helper for <input type=“file” />

Question

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?

Answer 1

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

Answer 2

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\""))

Answer 3

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.

Answer 4

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

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

Answer 5

You can also use:

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

Answer 6

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.