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foreign key columns and null values

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answered on 08 Mar 2012, 07:43 PM

I've created a runaround that works for me.

I'd usualy create foreignKey column like this:

c.ForeignKey(m => m.Account, new SelectList(ViewBag.Accounts as IEnumerable<Account>, "IdAccount", "AccountName"));

But, now, at the top of the view, i modify collection for foreignKey lookup, adding "NULL" value I need:

@{
List<SelectListItem> accounts = new SelectList(ViewBag.Accounts as IEnumerable<Account>, "IdAccount", "AccountName").ToList();
accounts.Insert(0, new SelectListItem { Text = "", Value = "" });
}

And, only after that I create foreign key column:

c.ForeignKey(m => m.Account, new SelectList(accounts, "Value", "Text"));

answered on 08 Mar 2012, 08:52 PM

Thanks, Milos. I used your guidance to do this slightly differently for my scenario. Code placed here for others traveling this path. (I suggest bringing Scotch for this trip.)

I add the empty value in the controller when I populate the list. No changes needed in my view. In my example below, my lookup list is a "Profile" for an "AccountUser". This propulates the ViewData as per the MVC demo example.

private void PopulateProfiles()
{
var profiles = Context.Profiles.Select(s => new { Oid = s.Oid, s.ProfileName }).OrderBy(s => s.ProfileName).ToList(); // list from DB
profiles.Add(new { Oid = string.Empty, ProfileName = string.Empty }); // bogus empty one.
ViewData["profiles"] = profiles;
}