Following is my Employee class

public class Employee
    {
        public string ProjectName { get; set; }

        public string EmployeeName { get; set; }
    }

Assume I have following data

    var employees = new List<Employee>();
    employees.Add(new Employee() { ProjectName = "NA", EmployeeName = "John" });
    employees.Add(new Employee() { ProjectName = "NA", EmployeeName = "Adam" });
    employees.Add(new Employee() { ProjectName = "Project2", EmployeeName = "Luis" });
    employees.Add(new Employee() { ProjectName = "Project2", EmployeeName = "Rose" });
    employees.Add(new Employee() { ProjectName = "Project1", EmployeeName = "Michael" });
    employees.Add(new Employee() { ProjectName = "Project1", EmployeeName = "Duke" });
    employees.Add(new Employee() { ProjectName = "Project3", EmployeeName = "Jacob" });

As seen above, few employees have been assigned to Project and few of them are not assigned ("NA"). My requirement is to order these employees in below manner

1. First Show all employees who are not assigned to any project with employee name in ascending order
2. Then show the employees ordered by each project and for each project show the employees in ascending order of their name

Expected result for above example (printing project name & employee name together).

NA -> Adam
NA -> John
Project1 -> Duke
Project1 -> Michael
Project2 -> Luis
Project2 -> Rose
Project3 -> Jacob

CodePudding user response：

You can:

1. order by the equality between ProjectName and "NA"
2. then, order by ProjectName
3. then, order by EmployeeName

Example implementation:

var orderedEmployees = employees
    .OrderByDescending(e => e.ProjectName == "NA") // First, show all employees who are not assigned to any project
    .ThenBy(e => e.ProjectName) // Then show the employees ordered by each project
    .ThenBy(e => e.EmployeeName) // ...with employee name in ascending order
    .ToList();

That snippet gives the following result:

NA --> Adam
NA --> John
Project1 --> Duke
Project1 --> Michael
Project2 --> Luis
Project2 --> Rose
Project3 --> Jacob

Example fiddle here.

CodePudding user response：

var orderedEmployees = employees
    .OrderByDescending(e => e.ProjectName == "NA")
    .ThenBy(e => e.ProjectName)
    .ThenBy(e => e.EmployeeName);

CodePudding user response：

Lambda expressions should be more than enough for this problem

    List<Employee> sortedEmployees = employees.OrderByDescending(x => x.ProjectName == "NA").ThenBy(x => x.ProjectName).ToList();

Test it by yourself and play with the properties you can access with x => x.Properties.

Just one comment: Be careful for null strings. You said you will have "NA", but if there is any null, your sorting will fail. You can add a default constructor or a function to replace null for "" if needed.

CodePudding user response：

var sorted = employees
    .OrderByDescending(e => e.ProjectName == "NA")
    .ThenBy(e => e.ProjectName)
    .ThenBy(e => e.EmployeeName);

CodePudding user response：

employees
    .OrderByDescending(e => e.ProjectName == "NA")
    .ThenBy(e => e.ProjectName);