Lately I am working a lot with LINQ and all flavors like LINQ to XML, LINQ to XSD, LINQ to objects, etc.
Today I had to build some functionality in SharePoint where I had to split users in two groups based on a profile property in their User Profile.

In this article I will show you how I did this.

The users I have to query are stored in a DataView (represented by the variable webUsers) so that is my starting point. First, I have to create an instance of the UserProfileManager class. This is the connection with the User Profile Database.

Then I iterate the DataView and Cast every item to the row variable. In the DataRowView the AccountName column contains a domain\user value. Because it is an object and I need it multiple times I store it in a locale variable using the let keyword so I only have to cast it one time.

One of the great things is that you are allowed to combine multiple let’s and where statements. So, every AccountName that is null or empty will be filtered out.

If I would use the GetUserProfile method and pass an account which is not (yet) present in the profile database, this would result in an exception. That is why I first use a where query in combination with the UserExists method.

For readability, I use another let to store the value I need in the comparison. Now I can create an anonymous object with a boolean if the title was equal to student, and some other profile properties.

var profileManager = new UserProfileManager();
var users = (from DataRowView row in webUsers
             let accountName = (string)row["AccountName"]
             where !string.IsNullOrEmpty(accountName)
             where profileManager.UserExists(accountName)
             let userProfile = profileManager.GetUserProfile(accountName)
             let title = (userProfile["Title"] != null)
                ? (string)userProfile["Title"].Value
                : string.Empty
             select new
             {
                IsStudent = title == "student",
                Initials = (userProfile["Initials"] != null)
                  ? (string)userProfile["Initials"].Value
                  : string.Empty,
                LastName = (userProfile["LastName"] != null)
                  ? (string)userProfile["LastName"].Value
                  : string.Empty,
             }).AsEnumerable();


var employees = from employee in users
                where !employee.IsStudent
                select employee;

var students = from student in users
               where student.IsStudent
               select student;

Now, I can easily get all students and employees in different collections based on that boolean property. And never call the ProfileManager more than necessary.