/*
A Programmer's Introduction to C# (Second Edition)
by Eric Gunnerson
Publisher: Apress L.P.
ISBN: 1-893115-62-3
*/
// 22 - Delegates\Delegates as Static Properties
// copyright 2000 Eric Gunnerson
using System;
class Container
{
public delegate int CompareItemsCallback(object obj1, object obj2);
public void SortItems(CompareItemsCallback compare)
{
// not a real sort, just shows what the
// inner loop code might do
int x = 0;
int y = 1;
object item1 = arr[x];
object item2 = arr[y];
int order = compare(item1, item2);
}
object[] arr; // items in the collection
}
class Employee
{
Employee(string name, int id)
{
this.name = name;
this.id = id;
}
public static Container.CompareItemsCallback SortByName
{
get
{
return(new Container.CompareItemsCallback(CompareName));
}
}
public static Container.CompareItemsCallback SortById
{
get
{
return(new Container.CompareItemsCallback(CompareId));
}
}
static int CompareName(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
return(String.Compare(emp1.name, emp2.name));
}
static int CompareId(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
if (emp1.id > emp2.id)
return(1);
if (emp1.id < emp2.id)
return(-1);
else
return(0);
}
string name;
int id;
}
public class DelegatesasStaticProperties
{
public static void Main()
{
Container employees = new Container();
// create and add some employees here
employees.SortItems(Employee.SortByName);
// employees is now sorted by name
}
}
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