List generic search criteria .. are predicates helpful?

Hi Sri,

Yes, you can have a list of lists of objects and the syntax is exactly as you'd surmised:

List>  list = new List> ();

Hey thanks! Thats appreciable effort. I did mention a search string variable in the class to solve this issue.

Thinking further on this. Can we have a list of list of objects?

Say company 1 has a list of employees and company 2 has a list of employees and so on.. then we have a combined list of list of employees of n companies.. The best employee is rated on a search criteria based on individual company policies and then the best among all companies is decided upon a different global search criteria applying to all companies.

It may not be fair to call them search criteria anymore.. Oh ya predicate now makes perfect sense to generalize the term search.. search is a form of predicate..

Looks like possible.. So, is a syntax of the form List> possible??

Let me know

There's no need for the search criteria to be part of the Employee object but the predicate method does need to have access to the filter string as it can't be passed as a parameter. The filter string therefore needs to be available at class level which would be the case with a property of a control.

I've written this simple C# console app to demonstrate some of the power which predicates bring to .NET:

using System;

public class Program
{
    static string letters;

    public static void Main()
    {

        Console.Clear();      
        Console.Write("Enter first letter(s) of last name to filter by: ");
        letters = Console.ReadLine(); 

        Employee[] employees = new Employee[4];

        employees[0] = new Employee("John", "D", "Brown");
        employees[1] = new Employee("Fred", "P", "Bloggs");
        employees[2] = new Employee("David", "E", "Smith");
        employees[3] = new Employee("Colin","R", "Taylor");

        Employee[] filteredEmployees;

        filteredEmployees = Array.FindAll(employees, StartsWithLetters);

        Console.WriteLine("\nThose employees whose last names begin with '" + letters + "' are:\n");

        foreach(Employee employee in filteredEmployees)
        {
            Console.WriteLine(employee.FullName);
        }
       
        Console.ReadKey();

    }

    public static bool StartsWithLetters(Employee e)
    {
        return e.LastName.StartsWith(letters, StringComparison.InvariantCultureIgnoreCase);
    }

}

public class Employee
{

    string firstName, middleInitial, lastName;

    public string FirstName
    {
        get{ return firstName; }
    }
   

    public string MiddleInitial
    {
        get{ return middleInitial; }
    }

    public string LastName
    {
        get{ return lastName; }
    }

    public string FullName
    {
        get{ return firstName + " " + middleInitial + " " + lastName; }
    }

    public Employee(string first, string middle, string last)
    {
        firstName = first;
        middleInitial = middle;
        lastName = last;
    }
}