Question

I’m having trouble separating files that a user might post to separate input type=”file” fields. I have tried:

var UploadedPicture = Request.Files[0];
    if(Path.GetFileName(UploadedPicture.FileName) != String.Empty)
    {
        var ContentType = UploadedPicture.ContentType;
        var ContentLength = UploadedPicture.ContentLength;
        var InputStream = UploadedPicture.InputStream;
        Session["gMugshot"] = new byte[ContentLength];
        InputStream.Read((byte[])Session["gMugshot"], 0, ContentLength);
    }
    else
    {
        Session["gMugshot"] = new byte[0];
    }

But that only gets one file. I have tried

foreach (HttpPostedFile postedFile in Request.Files)
        {
            int contentLength = postedFile.ContentLength;
            string contentType = postedFile.ContentType;
            string fileName = postedFile.FileName;

            postedFile.SaveAs(@"c:\test\file" + index + ".tmp");
        } 

    }

But that doesn’t separate them (Also, I don’t want to save the file, I just want to store it in the database, but that part is no problem). They each need to go into separate database fields. I can get this working with a single image, but don’t know how to work with multiples. If possible I would like to work with the input type="file" fields rather than the FileUpload.GetHtml(initialNumberOfFiles:1, allowMoreFilesToBeAdded:false, includeFormTag:false) helper.

Is it possible to retrieve them by the ID of the input element?

Answer 1

When you add multiple input type=file elements to a page, the uploaded files are available in the Request.Files collection. You can iterate that as your code shows and perform whatever action you like on each file in the collection:

if(Request.Files.Count > 0){
    foreach(var file in Request.Files){
        ...
    }
}

If you have different input type=file for specific purposes, you can identify them by providing a name attribute:

<input type=file name="file1" />
<input type=file name="file2" />
<input type=file name="file3" />

The values in the name attribute are available in the Request.Files.AllKeys, which is an array of strings, so you can reference each item by its index e.g.

if(IsPost && Request.Files.Count > 0){
    var file3 = Request.Files[Array.IndexOf(Request.Files.AllKeys, "file3")];
    if(file3.ContentLength > 0){
        //there is a file there
    }
}