Suppose this is our entity’s schema name “new_test”
and it contains following fields
new_name
new_lastname
Using CrmSvcUtil we have created the Entities classes and Data Context class.
https://nishantrana.wordpress.com/2010/08/11/using-crmsvcutil/
Now this is how we could use LINQ to query data using query expression as well as method based query.
Create the instace of DataContext class named xrm
var myXrm =
new xrm(
“CRMOnPremise”);
To loop through all the test records
foreach (var testRecord in myXrm.new_tests)
{
// print the information
}
To select a specific record
var singleRecord = (
from myTest
in myXrm.
new_tests
where myTest.
new_lastname ==
“Rana”
select myTest).Single();
var singleRecord1 = myXrm.new_tests
.Single(t => t.new_lastname == “Rana”);
To select all the records having last name as Rana
var allRecord =
from myTest
in myXrm.
new_tests
where myTest.
new_lastname ==
“Rana”
select myTest;
var allRecords1 = myXrm.new_tests.
Where(t => t.new_lastname == “Rana”);
To order the records
var allRecOrder=
from myTest
in myXrm.
new_tests
orderby myTest.
new_name ascending
where myTest.
new_lastname==
“Rana”
select myTest;
var allRecOrder1 = myXrm.new_tests
.OrderBy(t => t.new_name)
.Where(t => t.new_lastname == “Rana”);
To select specific field instead of the entire record
var singleField =
from myTest
in myXrm.
new_tests
select myTest.
new_name;
var singleField1 = myXrm.new_tests
.Select(t => t.new_name);
To return specific fields
var specificFields = from myTest in myXrm.new_tests
select new { myTest.createdby, myTest.createdon };
var specificFields1 = myXrm.new_tests
.Select(t => new { t.createdby, t.createdon });
Use of Take and Skip function
Take returns the given number of elements and ignores the rest
Skip skips the given number of elements and yielding the rest
var takeField = (from myTest in myXrm.new_tests
select myTest.new_name).Take(2);
var takeField1 = myXrm.new_tests
.Take(2)
.Select(t => t.new_name);
var skipField = (from myTest in myXrm.new_tests
select myTest.new_name).Skip(2);
var skipField1 = myXrm.new_tests
.Skip(2)
.Select(t => t.new_name);
Join – similar to inner join
The ‘select’ and ‘orderBy’ calls may only reference
a single common entity type.
We will get above error if we try to retrieve value from the other entity involved in join
var joinRecords =
from t
in myXrm.
new_tests
join s
in myXrm.systemusers on
t.ownerid.Value equals s.systemuserid
select new {t.
new_name };
var joinRecords1=myXrm.new_tests
.Join(myXrm.systemusers,
t=>t.ownerid.Value,
s=>s.systemuserid ,
(t,s)=>new {t.new_name});
Where conditions with Contains,StartsWith, EndsWith and
Equal string functions
var test1 =
from p
in myXrm.
new_tests
where p.
new_name.Contains(
“R”)
select p;
var test2 =
from p
in myXrm.
new_tests
where p.
new_name.StartsWith(
“R”)
select p;
var test3=
from p
in myXrm.
new_tests
where p.
new_name.EndsWith(
“D”)
select p;
var test11 = myXrm.new_tests
.Where(t => t.new_name.Contains(“R”));
var test22 = myXrm.new_tests
.Where(t => t.new_name.StartsWith(“R”));
var test32 = myXrm.new_tests
.Where(t => t.new_name.EndsWith(“D”));
Download the project :-
http://www.box.net/shared/xbg0xd5p7m
Bye..
Nishant Rana's Weblog 