LINQ question

ssezotman · August 30th, 2014, 02:44 PM

Hello Imar and TIA:

I am adapting the ASP.Net 4 book to (Ch. 16 with LINQ) to ASP.NET 4.5

In VS4 I have the following:

XYZDataContent db = new XYZDataContent();

var query = from customer in db.Customers where Customer.UserName == User.Identity.Name select Customer.Customer_ID;

I have a customer table with 2 fields 1) Customer_ID (keyfield and Is_identity turned on) and 2) UserName nvarchar field that is their first and last name.

I manually update this customer table and then using a Login control (Ch. 16) assign them a User Name and password for their access.

In the WHERE clause (I get an error in VS4.5) what I want to match is the person that just successfully logged in with their UserName in my existing customer table and then parse the Customer_ID which is unique only to them.

I am now using Entities so I have:

using (XYZEntities myEntities = new XYZEntities())

I need a little help with the new LINQ query

Thanks so much again,
Cliff

Imar · August 30th, 2014, 05:56 PM

Hi there,

Can you elaborate on this? I missing the question you're asking.

Cheers,

Imar

ssezotman · August 30th, 2014, 06:31 PM

Hi Imar:

Based upn your ASP.Net 4.0 book I have the following code:

XYZDatabaseContext db = new XYZDatabaseContext();

var query = from Customer in db.Customers where Customer.UserName == User.Identity.Name select Customer.Customer_ID

The idea here is to match a user that has just logged in with a Login control with hs Customer_ID that I have in a Customer table.I'm after the Customer_ID value (an int). This code worked just fine.

I am now going through the 4.5 book where you are talking about Entity Frameworks and I am trying to translate the old 4.0 version (above) into a similar 4.5 version. I have the following:

using (XYZEntities myEntities = new XYZEntities())
{
var query = from customer in myEntities.Customers
where customer.UserName == User.Entity.Name
select customer;

I am getting errors on the WHERE line.
Wondering if you could help.

Thank you,
Clliff

Imar · August 30th, 2014, 07:02 PM

Hi Clliff,

It would be very helpful if you posted your error message(s) along with the question. Otherwise, I need to create a new site, create a database, create an EF model, create a page, type in your code and run it to see what;s going on which, as I am sure you can imagine, might take a while.

Cheers,

Imar

ssezotman · August 30th, 2014, 07:59 PM

Hi and TIA:

using (XYZEntities myEntities = new XYZEntities())
{

var query = from customer in myEntities.Customers
where customer.UserName == User.Entity.Name
select customer;

I receive the following errors: (All 3 point to the where clause)

Error 3 'System.Security.Principal.IPrincipal' does not contain a definition for 'Entity' and no extension method 'Entity' accepting a first argument of type 'System.Security.Principal.IPrincipal' could be found (are you missing a using directive or an assembly reference?) C:\GolfHandicap(Local Host)\Site\Management\Players.aspx.cs 32 56 Site(3)

Error 1 Cannot convert lambda expression to type 'string' because it is not a delegate type C:\GolfHandicap(Local Host)\Site\Management\Players.aspx.cs 32 24 Site(3)

Error 2 Delegate 'System.Func<GolfDatabaseModel.Customer,int,bool>' does not take 1 arguments C:\GolfHandicap(Local Host)\Site\Management\Players.aspx.cs 32 24 Site(3)

Thanks for looking,
Cliff

Imar · August 31st, 2014, 03:03 PM

Ah, that helps. It's Identity, not Entity....

Imar