Retrieving list of Entities

Question

In CRM 2011 I can do the usual Create, Update, Delete operations using EarlyBoundEntities. I cant, however, seem to find an example of retrieving a list of entities using the same type of code. Is there a way of retrieving a list of items of type using EarlyBoundEntities?

I've looked through MSDN and all I can find is how to retrieve an Entity if I know its GUID already.

 // Retrieve the account containing several of its attributes.
 ColumnSet cols = new ColumnSet(
                new String[] { "name", "address1_postalcode", "lastusedincampaign" });

 Account retrievedAccount = (Account)_service.Retrieve("account", _accountId, cols);
 Console.Write("retrieved, ");

How would I for example get a list of all accounts which didnt have a phone number?

Answer 1

If you've generated your early-bound proxy classes with the servicecontextname parameters, then you could LINQ for querying.

var context = new XrmServiceContext(service);
var accounts = context.AccountSet.Where(item => item.Telephone1 == null);

Otherwise, if you still wanted to use other query methods such as QueryExpression you could use LINQ to cast all instances to the desire early-bound type.

var contacts = service.RetrieveMultiple(new QueryExpression
                                            {
                                                EntityName = "contact",
                                                ColumnSet = new ColumnSet("firstname")
                                            })
    .Entities
    .Select(item => item.ToEntity<Contact>());

You could also use an extension method if you'd prefer:

public static IEnumerable<T> RetrieveMultiple<T>(this IOrganizationService service, QueryBase query) where T : Entity
{
    return service.RetrieveMultiple(query)
        .Entities
        .Select(item => item.ToEntity<T>());
}

Usage:

var contacts = service.RetrieveMultiple<Contact>(new QueryExpression
                                                        {
                                                            EntityName = "contact",
                                                            ColumnSet = new ColumnSet("firstname")
                                                        });

Answer 2

There's actually plenty of material in the SDK on MSDN that shows how to query an entity.

Create Queries to Retrieve Data

Build Queries with LINQ - primarily early-bound examples

The API provides three more or less equivalent ways to query the database (LINQ, FetchXml, and QueryExpression), though there are limitations (for example, see LINQ limitations) that you can only get around by using an on-premise installation and native SQL calls.

For the example of the accounts with a null phone number that you gave, though, any of the three supported query methods will work.