Try attaching to the BeforeSubmittingPostedData event for your XFormControl instance and set your file upload values direcly to the e.FormData object in your event arguments. Here´s a sample from the sdk:
EPiServer Development Team
I saw this in the SDK:
XForm form = new XForm();
XFormData data = form.CreateFormData();
NameValueCollection values = data.GetValues();
foreach(String key in values)
data.ChannelOptions = ChannelOptions.Database;
data.Send(); // In 4.51 you have to call data.Send(data.FormId);
But I didn't see anything about e.FormData.SetValue. I couldn't figure out how to add to the same form instead of a new form created.
I created a custom page type that is a mix of using a regular xform created in Edit mode, and I have added a custom file upload tool at the top of the page. I added a custom button submit, and on submit it stores the xform data using:
I've stored the file names uploaded into an array. How do I also add these files names (not actual files, just names) into the database? I'm not sure how I append to the database fields stored using ChannelOptions.