Upload multiple files using HttpFileCollectionBase issue with C# and MVC3

Question

I created a controller which save files.

The below code is a part of that Controller:

if ( Request.Files.Count != 0 ) {
      HttpFileCollectionBase files = Request.Files;

      foreach ( HttpPostedFileBase file in files ) {
            if ( file.ContentLength > 0 ) {
               if ( !file.ContentType.Equals( "image/vnd.dwg" ) ) {
                  return RedirectToAction( "List" );
               }
            }
         }
 }

in ASPX page is simple:

<input type="file" name="file" />
<input type="file" name="file" />
...// many inputs type file

The problem is foreach because it returns an error like (I know because I run in Debug mode and placed breakpoint at foreach statement):

Unable to cast object of type 'System.String' to type 'System.Web.HttpPostedFileBase'.

What is my mistake ?

Darin Dimitrov · Accepted Answer · 2012-02-29 14:09:20Z

11

Try like this:

[HttpPost]
public ActionResult Upload(IEnumerable<HttpPostedFileBase> files)
{
    if (files != null && files.Count() > 0)
    {
        foreach (var uploadedFile in files)
        {
            if (uploadedFile.ContentType != "image/vnd.dwg") 
            {
                return RedirectToAction("List");
            }

            var appData = Server.MapPath("~/app_data");
            var filename = Path.Combine(appData, Path.GetFileName(uploadedFile.FileName));
            uploadedFile.SaveAs(filename);                    
        }
    }

    return RedirectToAction("Success");
}

and modify the markup so that the file inputs are named files:

<input type="file" name="files" />
<input type="file" name="files" />
...// many inputs type file

answered Feb 29, 2012 at 14:09

Darin Dimitrov

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3 Comments

Snake Eyes Over a year ago

I tried the above code (it seems with my code) but I changed my mind regarding to foreach. I'm using now the for statement. And it works good.

Snake Eyes Over a year ago

and the last mention: I have no parameters in my controller function

HelloWorld1 Over a year ago

I tried this solution but I don't retrieve any value!

Henry · Accepted Answer · 2017-03-14 03:32:29Z

3

for (int i = 0; i < Request.Files.Count; i++)
{
    var file = Request.Files[i];
    // this file's Type is HttpPostedFileBase which is in memory
}

HttpRequestBase.Files requires an index, so use for instead of foreach.

edited Mar 14, 2017 at 3:32

answered Jul 12, 2016 at 3:13

Henry

314 bronze badges

Comments

Lazarus · Accepted Answer · 2012-02-29 14:10:49Z

2

Have a look at this post by Phil Haack which demonstrates how to process multiple file uploads using MVC. The object you are trying to use is for ASP.NET Webforms.

answered Feb 29, 2012 at 14:10

Lazarus

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