Querying an Account using QueryByAttribute, FetchXML and LINQ

Using the late bound method, here is the same query results using QueryByAttribute, FetchXML and LINQ.  For this example, I wrote a simple Console Application in Visual Studio 2012.

1. Create a new project and choose Console Application template.
2. In Solution Explorer, expand the References folder and add the Microsoft.Xrm.Sdk.dll and Microsoft.Xrm.Client.dll from the CRM SDK /bin folder
   
3. Also add the System.Runtime.Serialization Assembly
   
   
4. Your References should look similar to this:
   
5. In the code for Program.cs the using statements need to include the following:
   
6. Inside the Main method, the CrmConnection class is used to connect to Dynamics CRM.
   
7. Use the OrganizationService and OrganizationServiceContext classes to setup the service and orgContext objects.
   
8. Code for the query expression (QueryByAttribute)
   

   Console.WriteLine(“==QueryByAttribute==”); QueryByAttribute qba = new QueryByAttribute(“account”); qba.ColumnSet = new ColumnSet(“name”); qba.Attributes.AddRange(“name”); qba.Values.AddRange(“ACME”); EntityCollection ecqba = service.RetrieveMultiple(qba); foreach (Entity acct in ecqba.Entities) { Console.WriteLine(acct.Attributes[“name”]); }

9. Code for LINQCode for FetchXML
   

   Console.WriteLine(“==FetchXML==”); string fetch = @” <fetch mapping=’logical’> <entity name=’account’> <attribute name=’name’/> <filter type=’and’> <condition attribute=’name’ operator=’eq’ value=’ACME’ /> </filter> </entity> </fetch>”; EntityCollection ecf = service.RetrieveMultiple(new FetchExpression(fetch)); foreach (Entity acct in ecf.Entities) { Console.WriteLine(acct.Attributes[“name”]); }

10. Console.WriteLine(“==LINQ==”); var linq = from a in orgContext.CreateQuery(“account”) where (a[“name”].Equals(“ACME”)) select a[“name”]; foreach (var acct in linq) { Console.WriteLine(acct); }

11. The output should look like this: