Add users to the site collection administrator group through code

Question

You can add users to the site collection administrators group through
Site Actions ->Site Collection Administrators (and add users)

But how can you do this through code? What is the grpName?

web.EnsureUser(User.LoginName);
web.SiteGroups[grpName].AddUser(@User.LoginName, string.Empty, LookupValue, string.Empty);

Answer 1

You need to get the SPUser object for a user in a Site Collection and update the IsSiteAdmin property.

function makeUserSiteCollectionAdmin(SPUser user)
{
    user.IsSiteAdmin = true;
    user.Update();
}