Create User profile with separate social media data

I am creating user profile logic for a blogging platform. I have the UserProfile model and then two separate models, UserSocialLink and SocialLinkType to control the user's various social media contacts (i.e. Facebook, Twitter, Google+, etc...). I am looking for feed back on the execution of the methods used to Add new UserProfiles. Is this the way you would handle it? Is there a better way? What are some of the issues you see with my methods (specifically in the service class)?

The Models

public class UserProfile
{
    public int Id { get; set; }
    public string UserName { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string ProfilePicUrl { get; set; }
    public string Location { get; set; }
    public string DateOfBirth { get; set; }
    public string Bio { get; set; }
    public DateTime Created { get; set; }
    public DateTime Updated { get; set; }
 }

public class UserSocialLink
{
    public int Id {get; set;}
    public int UserProfileId { get; set; }
    public int SocialLinkTypeID { get; set; }
    public string LinkValue { get; set; }
    public DateTime Created { get; set; }
    public DateTime Updated { get; set; }

    public virtual UserProfile UserProfile { get; set; }
    public virtual SocialLinkType SocialLinkType {get; set;}
}

public class SocialLinkType
{
    public int Id { get; set; }
    public string LinkType { get; set; }
    public string URLFormat { get; set; }
}

The Add Methods in The Service Class

```
public class UserProfileService : IUserProfileService
{
public UserProfile Add(UserProfile userProfile)
{
var now = DateTime.UtcNow;

if (userProfile == null)
throw new ArgumentNullException("User Profile");

userProfile.Created = now;
userProfile.Updated = now;
using (var db = new ApplicationDbContext())
{
db.UserProfiles.Add(userProfile);
db.SaveChanges();

public UserProfile AddSocialLink(string userName, UserSocialLink userSocialLink, string socialLinkType)

Shouldn't the socialLinkType be a property of the UserSocialLink class? It seems odd to me that the code has to pass a string along with the object in order to tell the method what type it is. That said, I really do like that you're checking the database to make sure the type is valid. Now that I think of it, why pass the user name as a string? Wouldn't it be a simpler API to pass a UserProfile in? At least, it would be more consistent for the dev using the UserProfileService.

This code is a great example of why we should all use proper indentation and braces around if statements.

var linkType = db.SocialLinkTypes.SingleOrDefault(p => p.LinkType.ToUpper() == socialLinkType.ToUpper());
if (linkType == null)
    throw new Exception("Social Media Type Not Found");
userSocialLink.Created = now;
userSocialLink.Updated = now;
userSocialLink.SocialLinkTypeID = linkType.Id;
db.UserSocialLinks.Add(userSocialLink);
db.SaveChanges();
return userProfile;

At a glance, it looks like the userSocialLink only gets it's properties set if (linkType == null) and after an exception is thrown. Of course, this is ridiculous and not what is actually happening, but braces make that crystal clear to Mr. Maintainer.

var linkType = db.SocialLinkTypes.SingleOrDefault(p => p.LinkType.ToUpper() == socialLinkType.ToUpper());
if (linkType == null)
{
    throw new Exception("Social Media Type Not Found");
}
userSocialLink.Created = now;
userSocialLink.Updated = now;
userSocialLink.SocialLinkTypeID = linkType.Id;
db.UserSocialLinks.Add(userSocialLink);
db.SaveChanges();
return userProfile;

StackExchange Code Review Q#64053, answer score: 4