Use late-bound Entity class with a LINQ query

In Microsoft Dataverse, you can use late binding with .NET Language-Integrated Query (LINQ) queries. Late binding uses the attribute logical name, and is resolved at runtime.

Using late binding in a JOIN clause

The following examples show how to use late binding in the join clause of a LINQ query.

Retrieve the full name of the contact that represents the primary contact for an account and the account name.

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
var query_join2 = from c in orgSvcContext.CreateQuery("contact")
                  join a in orgSvcContext.CreateQuery("account")
                  on c["contactid"] equals a["primarycontactid"]
                  select new
                  {
                   contact_name = c["fullname"],
                   account_name = a["name"]
                  };
foreach (var c in query_join2)
{
 System.Console.WriteLine(c.contact_name + "  " + c.account_name);
}
}

Retrieve Contact, Account and Lead data where the Lead was the originating Lead and the Contact’s last name is not “Parker”

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
var query_dejoin = from c in orgSvcContext.CreateQuery("contact")
                   join a in orgSvcContext.CreateQuery("account") 
                   on c["contactid"] equals a["primarycontactid"]
                   join l in orgSvcContext.CreateQuery("lead") 
                   on a["originatingleadid"] equals l["leadid"]
                   where (string)c["lastname"] != "Parker"
                   select new { Contact = c, Account = a, Lead = l };
foreach (var c in query_dejoin)
{
 System.Console.WriteLine(c.Account.Attributes["name"] + " " + 
  c.Contact.Attributes["fullname"] + " " + c.Lead.Attributes["leadid"]);
}
}

Using late binding in a left JOIN

The following example shows how to retrieve a list of Contact and Account information using a left join. A left join is designed to return parents with and without children from two sources. There is a correlation between parent and child, but no child may actually exist.

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
var query_join9 = from a in orgSvcContext.CreateQuery("account")
                  join c in orgSvcContext.CreateQuery("contact") 
                  on a["primarycontactid"] equals c["contactid"] into gr
                  from c_joined in gr.DefaultIfEmpty()
                  select new
                  {
                   account_name = a.Attributes["name"]
                  };
foreach (var c in query_join9)
{
 System.Console.WriteLine(c.account_name);
}
}

Using late binding and the Contains method

The following example shows how to use late binding with the Contains method in a LINQ query.

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
var query_contains3 = from c in orgSvcContext.CreateQuery("contact")
                      where ((string)c["description"]).Contains("Coho")
                      select new
                      {
                       firstname = c.Attributes["firstname"],
                       lastname = c.Attributes["lastname"]
                      };
foreach (var c in query_contains3)
{
 System.Console.WriteLine(c.firstname + " " + c.lastname);
}
}

Using late binding and NOT Equals operator

The following example shows use of the not equals operator.

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{
var query_ne3 = from c in orgSvcContext.CreateQuery("contact")
                where !c["address1_city"].Equals(null)
                select new
                {
                 FirstName = c["firstname"],
                 LastName = c["lastname"],
                 Address1_City = c["address1_city"]
                };
foreach (var c in query_ne3)
{
 System.Console.WriteLine(c.FirstName + " " + 
  c.LastName + " " + c.Address1_City);
}
}

Using the GetAttributeValue method

The following example shows how to retrieve Contact information using the GetAttributeValue method.

using (OrganizationServiceContext orgSvcContext = new OrganizationServiceContext(_serviceProxy))
{

var list_getattrib1 = (from c in orgSvcContext.CreateQuery("contact")
                       where c.GetAttributeValue<Guid?>("contactid") != _contactId1
                       select new { 
                        FirstName = c.GetAttributeValue<string>("firstname"), 
                        LastName = c.GetAttributeValue<string>("lastname") 
                       }).ToList();
foreach (var c in list_getattrib1)
{
 System.Console.WriteLine(c.FirstName + " " + c.LastName);
}
}

See also

Build Queries with LINQ (.NET Language-Integrated Query)
Order results using table columns with LINQ
CreateQuery<TEntity>()