How to use Linq to Entities in ApplicationOAuthProvider asp.net web api2 - asp.net-mvc

Question

this code return error does not support linq to entities, please help me
error return is
LINQ to Entities does not recognize the method 'System.String get_Item(System.String)' method, and this method cannot be translated into a store expression.
problem in this line
ApplicationUser user = dbContext.Users.Where(s => s.UserName == context.UserName && s.Password == context.Password && s.CodeID == data["CodeID"]);
public class ApplicationOAuthProvider : OAuthAuthorizationServerProvider
{
private readonly string _publicClientId;
public ApplicationOAuthProvider(string publicClientId)
{
if (publicClientId == null)
{
throw new ArgumentNullException("publicClientId");
}
_publicClientId = publicClientId;
}
public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
{
var userManager = context.OwinContext.GetUserManager<ApplicationUserManager>();
var data = await context.Request.ReadFormAsync();
ApplicationUser user = await userManager.FindAsync(context.UserName, context.Password);
ApplicationDbContext dbContext = new ApplicationDbContext();
//here problem
//does not support linq to entities
ApplicationUser user = dbContext.Users.Where(s => s.UserName == context.UserName && s.Password == context.Password && s.CodeID == data["CodeID"]);
//here problem
if (user == null)
{
context.SetError("invalid_grant", Resources.Resources.Invalid_UsernamePassword);
return;
}
ClaimsIdentity oAuthIdentity = await user.GenerateUserIdentityAsync(userManager,
OAuthDefaults.AuthenticationType);
ClaimsIdentity cookiesIdentity = await user.GenerateUserIdentityAsync(userManager,
CookieAuthenticationDefaults.AuthenticationType);
AuthenticationProperties properties = CreateProperties(user.UserName);
AuthenticationTicket ticket = new AuthenticationTicket(oAuthIdentity, properties);
context.Validated(ticket);
context.Request.Context.Authentication.SignIn(cookiesIdentity);
}
public override Task TokenEndpoint(OAuthTokenEndpointContext context)
{
foreach (KeyValuePair<string, string> property in context.Properties.Dictionary)
{
context.AdditionalResponseParameters.Add(property.Key, property.Value);
}
return Task.FromResult<object>(null);
}
public override Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
{
// Resource owner password credentials does not provide a client ID.
if (context.ClientId == null)
{
context.Validated();
}
return Task.FromResult<object>(null);
}
public override Task ValidateClientRedirectUri(OAuthValidateClientRedirectUriContext context)
{
if (context.ClientId == _publicClientId)
{
Uri expectedRootUri = new Uri(context.Request.Uri, "/");
if (expectedRootUri.AbsoluteUri == context.RedirectUri)
{
context.Validated();
}
}
return Task.FromResult<object>(null);
}
public static AuthenticationProperties CreateProperties(string Username)
{
IDictionary<string, string> data = new Dictionary<string, string>
{
{ "Username", Username }
};
return new AuthenticationProperties(data);
}
}

Answer 1

Linq to entities cannot convert this part:
s.CodeID == data["CodeID"]
Which retrieves the CodeID value from the data collection into a meaningful SQL statement.
What you have to do is store this value in a variable before your where expression like so:
var codeId = data["CodeID"];
and then modify your where to use it:
var codeId = data["CodeID"];
ApplicationUser user = dbContext.Users.Where(s => s.UserName == context.UserName && s.Password == context.Password && s.CodeID == codeId);
Now Linq can properly generate the SQL statement.