Extract property of object from entity framework query

Question

I'm new to EF and I'm having trouble doing the simplest thing...

public class Person : DTO
{
    public String ID { get; set; }
    public String Fname { get; set; }
    public String Lname{ get; set; }
}

I would like to use either IQueryable<Person> or ObjectReuslt<Person> to extract Fname from my object.

 peopleEntities entities = new peopleEntities();
 string queryStr = "select value c from peopleEntity.Person as c Where c.ID=" + personID;
 IQueryable<EntityObject> query = entities.CreateQuery<EntityObject>(queryStr);

I see that CreateQuery can both return IQueryable and ObjectResult. I'd like to know whats the lightest way that I can extract Fnames into a list from my query result.

Why are you writing sql queries when using EF? you lose all the strongly typed awesomeness that EF gets you — Kritner
– Kritner, Commented Jul 27, 2015 at 13:48
@Kritner Well, entity table name is supposed to be dynamic and I thought formatting sql string was the easiest. What do u think? Create query will not let me do something like... select fname from peopleEntity.Person ... — lzc
– lzc, Commented Jul 27, 2015 at 13:51

Kritner · Accepted Answer · 2015-07-27 14:08:06Z

0

I'm interpreting your question as "Get the first name of the provided personId". Assuming your peopleEntities contains a DbSet<Person> Person you could do the following:

public string GetFirstNameForPeron(string personId)
{
    peopleEntities entities = new peopleEntities(); // new up your EF context

    return entities
        .Person // from the person entities
        .Where(w => w.ID == personId) // Where the ID = personId
        .FirstOrDefault(); // take the first available
        .Fname; // only the Fname property
}

answered Jul 27, 2015 at 14:08

Kritner

13.8k11 gold badges53 silver badges76 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

lzc Over a year ago

So what if the entity Person and field Fname are dynamic. Meaning I don't know which entity I am dealing with, and also don't know the field I want.

Kritner Over a year ago

That sounds like a very different scenario that what you're asking about in your question. stackoverflow.com/questions/21084916/…

Collectives™ on Stack Overflow

Extract property of object from entity framework query

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related