Insert into bridge table entity framework - asp.net

Question

Hi guys,
I'm learning to climb with EF ,I do have basic understanding of CRUD with EF ,but now I have a table which have a navigation property (Which I suspect is the bridge table) ,so I need to add value into the bridge table ,I think I can do it with navigational property.
Problem Explained:
Original partial DB Diagram
Partial EF Model Diagram
Code I Wrote:
protected void BtnAddUser_Click(object sender, EventArgs e)
{
DBEntities entities = new DBEntities();
var usr = new User();
//I thought I would add an Roles object into usr.UserRoles.Add(usrRoles);
//but UserRoles have only two fields ,RoleTypeId and UserId
//var usrRoles = new Roles()
//{Id=0,RoleDescription="dfdfdf",RoleType="WebSite Admin"};
usr.UserName = TxtbxUserName.Text;
usr.Password = TxtBxPassword.Text;
usr.Email = TxtbxEmail.Text;
usr.CreateDate = DateTime.Now;
usr.LastActivityDate = DateTime.Now;
usr.IsEnabled = true;
//What to Add in the .Add method
usr.UserRoles.Add(
entities.User.AddObject(usr);
int result = entities.SaveChanges();
LblMsg.Text = result == 1 ? "User created successfully." : "An error occured ,please try later.";
entities.Dispose();
}
Update (What I have tried so far):
I fetch "Website Admin" role from roles table and put it into ObjectContext.UserRoles.Add(UserRoleWebsiteAdmin);
So that what I did in the code,
//Fetch WebsiteAdmin from Roles
var userRole = from usrRole in entities.Roles
where usrRole.Id == 1
select usrRole;
usr.UserName = TxtbxUserName.Text;
//same old code of usr.Property = someTextBox
//I have tried to type cast it LinqtoEntities result into Roles
usr.UserRoles.Add((Roles)userRole);
Exception generated
P.S: Let me know if you need more clarification.

Answer 1

Maybe you can use using http://msdn.microsoft.com/en-us/library/yh598w02.aspx and object initializer http://msdn.microsoft.com/en-us/library/bb384062.aspx for better readability so:
using(DBEntities entities = new DBEntities())
{
//Make user object
var user = new User{
UserName = TxtbxUserName.Text,
Password = TxtBxPassword.Text,
Email = TxtbxEmail.Text,
CreateDate = DateTime.Now,
LastActivityDate = DateTime.Now,
IsEnabled = true
};
//Fetch type of Role from Roles table
var userRole = entities.Roles.Where(x=>x.usrRole.Id ==1).Single();
user.UserRoles.Add(userRole);
entities.User.AddObject(user);
int result = entities.SaveChanges();
LblMsg.Text = result == 2 ? "User created succesfully." : "An error occured ,please try later.";
}
Regards

Answer 2

Well thanks guys...
Here what I have done and it works,
DBEntities entities = new DBEntities();
//Make user object
var usr = new User();
//Fetch type of Role from Roles table
var userRole = (from usrRole in entities.Roles
where usrRole.Id == 1
select usrRole).Single();
//copy user related info from textboxes
usr.UserName = TxtbxUserName.Text;
usr.Password = TxtBxPassword.Text;
usr.Email = TxtbxEmail.Text;
usr.CreateDate = DateTime.Now;
usr.LastActivityDate = DateTime.Now;
usr.IsEnabled = true;
usr.UserRoles.Add(userRole as Roles);
entities.User.AddObject(usr);
int result = entities.SaveChanges();
LblMsg.Text = result == 2 ? "User created succesfully." : "An error occured ,please try later.";
entities.Dispose();