<t>Here's how I do it.<br/>
<br/>
I decided to use IPrincipal instead of IIdentity because it means I don't have to implement both IIdentity and IPrincipal.<br/>
<br/>
<br/>
Create the interface<br/>
<br/>
interface ICustomPrincipal : IPrincipal<br/>
{<br/>
int Id { get; set; }<br/>
string FirstName { get; set; }<br/>
string LastName { get; set; }<br/>
}<br/>
<br/>
```<br/>
<br/>
- <br/>
CustomPrincipal<br/>
<br/>
```<br/>
public class CustomPrincipal : ICustomPrincipal<br/>
{<br/>
public IIdentity Identity { get; private set; }<br/>
public bool IsInRole(string role) { return false; }<br/>
<br/>
public CustomPrincipal(string email)<br/>
{<br/>
this.Identity = new GenericIdentity(email);<br/>
}<br/>
<br/>
public int Id { get; set; }<br/>
public string FirstName { get; set; }<br/>
public string LastName { get; set; }<br/>
}<br/>
<br/>
```<br/>
<br/>
- <br/>
CustomPrincipalSerializeModel - for serializing custom information into userdata field in FormsAuthenticationTicket object.<br/>
<br/>
```<br/>
public class CustomPrincipalSerializeModel<br/>
{<br/>
public int Id { get; set; }<br/>
public string FirstName { get; set; }<br/>
public string LastName { get; set; }<br/>
}<br/>
<br/>
```<br/>
<br/>
- <br/>
LogIn method - setting up a cookie with custom information<br/>
<br/>
```<br/>
if (Membership.ValidateUser(viewModel.Email, viewModel.Password))<br/>
{<br/>
var user = userRepository.Users.Where(u => u.Email == viewModel.Email).First();<br/>
<br/>
CustomPrincipalSerializeModel serializeModel = new CustomPrincipalSerializeModel();<br/>
serializeModel.Id = user.Id;<br/>
serializeModel.FirstName = user.FirstName;<br/>
serializeModel.LastName = user.LastName;<br/>
<br/>
JavaScriptSerializer serializer = new JavaScriptSerializer();<br/>
<br/>
string userData = serializer.Serialize(serializeModel);<br/>
<br/>
FormsAuthenticationTicket authTicket = new FormsAuthenticationTicket(<br/>
1,<br/>
viewModel.Email,<br/>
DateTime.Now,<br/>
DateTime.Now.AddMinutes(15),<br/>
false,<br/>
userData);<br/>
<br/>
string encTicket = FormsAuthentication.Encrypt(authTicket);<br/>
HttpCookie faCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encTicket);<br/>
Response.Cookies<br/>
<br/>
*(Réponse tronquée)*</t>
