Webinar presented for European SharePoint Community on 14-06-2011, about LINQ to SharePoint, including common pitfalls and performance.

1. LINQ to SharePoint
André Vala
andre.vala@create.pt

2. Agenda
• LINQ?
• LINQ to SharePoint?
• Developing with LINQ
• Common Pitfalls
• Performance
• Conclusion
2

3. LINQ?
3
LINQ PROVIDER DATA SOURCEAPPLICATION
B
C
A
.NET
.NET
QUERY
DATA
Language Integrated Query

4. LINQ to SQL
using System.Data.Linq;
DataContext db = new DataContext(@”mydatabase.mdf”);
Table<BankAccount> BankAccounts = db.GetTable<BankAccount>();
var query =
from account in BankAccounts
where account.Bank == “Deutsche Bank”
select account;
foreach (BankAccount account in query)
{
Console.WriteLine(“Number: {0}”, account.Number);
} 4

5. SHAREPOINT
LIST ITEMS
CAML
LINQ to SharePoint?
5
LINQ PROVIDER DATA SOURCEAPPLICATION
B
C
A
.NET
.NET
QUERY
DATA
SHAREPOINT
LINQ PROVIDER
Microsoft.SharePoint.Linq.dll

6. LINQ to SharePoint
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
EntityList<BankAccount> BankAccounts =
data.GetList<BankAccount>(“BankAccounts”);
var query =
from account in BankAccounts
where account.Bank == “Deutsche Bank”
select account;
foreach (BankAccount account in query)
{
Console.WriteLine(“Number: {0}”, account.Number);
}
6

7. DEMO HELLO LINQ!
7

8. Developing with LINQ
• Entities
• Add Items
• Delete Items
• Recycle Items
• Update Items
• Logging
8

9. Entities
BankAccount account = new BankAccount()
{
Number = “99100048169”,
Bank = “Deutsche Bank”
};
9
Content Type Entity Class
Column Attribute Member

10. Entities Manual Definition
[ContentType(Name=“BankAccount”, Id=“0x0104”)]
public partial class BankAccount
{
[Column(Name=“Number”, FieldType=“Text”)]
public string Number { get; set; }
[Column(Name=“Bank”, FieldType=“Text”)]
public string Bank { get; set; }
}
10

11. Entities Automatic Generation
SPMetal
Tool to generate entities for a set of content types / lists
Where is it?
C:Program FilesCommon FilesMicrosoft SharedWeb Server Extensions14BIN
How is it used?
SPMetal
/web:http://myserver/myweb
/code:BankAccounts.cs
/namespace:MyApp.SharePoint.Data
11

12. Add Items
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
BankAccount account = new BankAccount()
{
Number = “99100048169”,
Bank = “Deutsche Bank”
};
data.BankAccounts.InsertOnSubmit(account);
data.SubmitChanges();
12

13. Delete Items
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
foreach (BankAccount account in data.BankAccounts)
{
if (account.Bank == “Deutsche Bank”)
data.BankAccounts.DeleteOnSubmit(account);
}
data.SubmitChanges();
13

14. Recycle Items
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
foreach (BankAccount account in data.BankAccounts)
{
if (account.Bank == “Deutsche Bank”)
data.BankAccounts.RecycleOnSubmit(account);
}
data.SubmitChanges();
14

15. Update Items
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
foreach (BankAccount account in data.BankAccounts)
{
if (account.Bank == “Deutsche Bank”)
account.Bank = “Bank of America”;
}
data.SubmitChanges();
15

16. Logging
using Microsoft.SharePoint.Linq;
DataContext data = new DataContext(SPContext.Current.Web.Url);
StringWriter writer = new StringWriter();
data.Log = writer;
// LINQ queries
(...)
string caml = writer.ToString();
16

17. DEMO LINQING
17

18. Common Pitfalls
• Anonymous Access
• Display Names
18

19. Pitfall Anonymous Access
• LINQ to SharePoint has no support for
anonymous access
• There is a workaround but has disadvantages:
– Large performance impact
– Uses RunWithElevatedPrivileges
• Solution: go back to CAML...
19

20. DEMO ANONYMOUS ACCESS
20

21. Pitfall Display Names
• SPMetal uses column Display Names to
generate class members
• What happens when the column names have
special characters? Weird things happen…
• How can we solve it?
21

22. DEMO DISPLAY NAMES
22

23. Performance
• Object Tracking Enabled
• LINQ vs CAML
23

24. Performance Object Tracking Enabled
Optimizes the performancein read-only scenarios...
DataContext data = new DataContext(SPContext.Current.Web.Url);
data.ObjectTrackingEnabled = false;
24

25. Performance LINQ vs CAML
• The LINQ to CAML translation is performed in
real time
• There is a performance penalty
• The generated query can be inefficient
• Not all the operations offered with LINQ are
supported in CAML...
25

26. DEMO PERFORMANCE
26

27. Conclusion
LINQ to SharePoint is really simple to use but
not the solution when...
• The code must run on the client
• The solution must support anonymous access
• Performance is paramount
• There are lookup columns that refer to lists in
other web sites of the same site collection
27

28. Thank You
André Vala
andre.vala@create.pt