Question

I have the following code:

        var currentUser = (from i in _dbContext.Users
                           where i.FirstName == user.FirstName && i.LastName == user.LastName
                               && i.Title == user.Title && i.Company == user.Company
                           select i).FirstOrDefault();

                        currentUser.Company = user.Company;
                        currentUser.CompanyUrl = user.CompanyUrl;
                        currentUser.Country = user.Country;

                        _dbContext.SaveChanges();

but I got an error

{“Violation of UNIQUE KEY constraint ‘IX_Users’. Cannot insert
duplicate key in object ‘dbo.Users’. The duplicate key value is (a8,
b8, c8).\r\nThe statement has been terminated.”}

so, it says that EF tries to add new record instead of edit current. Why?

Answer 1

I think the problem will be combining user and currentUser. It most probably updates your currentUser but in the same time inserts user. The reason can be this:

currentUser.Company = user.Company;

If company has Users navigation property and if you are using POCO template this will connect both Company and user as new entities to the context.

Try this:

var currentUser = ...;

var company = new Company { Id = user.Company.Id };
_dbContext.Companies.Attach(company);

currentUser.Company = company;
...

_dbContext.SaveChanges();