Like this article? We recommend
Like this article? We recommend
Like this article? We recommend
Searching a Generic Collection
To search a collection, I use what's called a predicate; that is, a delegate type for a method. This is simply a method that carries out the required search by using a supplied set of criteria. Depending on the criteria, the method returns either true or false. Listing 13 contains an example of a simple predicate.
Listing 13 A predicate method.
private static bool AnotherEmployee(Person p)
{
if (p.Name.Equals("Another Employee"))
{
Console.WriteLine("Managed to locate: " + "Another Employee");
return true;
}
else
{
return false;
}The method in Listing 13 simply checks the name of the Person object passed into it and returns a Boolean value. Each element of the collection is passed into the search method until a match is found. This process probably sounds much more complicated than it is! The following single line of code invokes the Listing 13 method:
genericCollection.MyGenericCollection.Find(AnotherEmployee);
Notice that the delegate name is simply passed into the Find() method. Listing 14 holds the program output.
Listing 14 Program output indicating the successful collection search.
Collection capacity: 0 Person called: An Employee Person called: A Contractor Person called: Another Employee Number of entries: 3 Name is An Employee Name is A Contractor Name is Another Employee
Sorted name is A Contractor Sorted name is An Employee Sorted name is Another Employee Managed to locate: Another Employee
Notice the end of Listing 14 that the code has searched the generic collection and located the required element.