Generic collection in c sharp

Question

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Oues-: What is  Generic collection in c sharp with example ?

Datta Kharad · Answer

Hi
Generic Collection:-
A generic collection is strongly typed (type safe), meaning that you can only put one type of object into it. This eliminates type mismatches at runtime. Another benefit of type safety is that performance is better with value type objects because they don't incur overhead of being converted to and from type object. With generic collections, you have the best of all worlds because they are strongly typed, like arrays, and you have the additional functionality, like ArrayList and other non-generic collections, without the problems.
Creating Generic List Collections
The pattern for using a generic List collection is similar to arrays. You declare the List, populate its members, then access the members. Here's a code example of how to use a List:
List myInts = new List ();
myInts.Add(1);
myInts.Add(2);
myInts.Add(3);
for (int i = 0; i , which is referred to as List of int. If you looked in the documentation for this class, you would find that it is defined as List , where T could be any type. For example, if you wanted the list to work on string or Customer objects, you could define them as List or List and they would hold only string or Customer objects. In the example above, myInts holds only type int.
Main collection classes which are used in c# as
· ArrayList Class
· HashTable Class
· Stack Class and Queue class etc.
The main properties of the collection classes are
· Collection classes are defined as part of the System.Collection or System.Collections.Generic namespace.
· Most collection classes derive from the interfaces ICollection, IComparer, IEnumerable, IList, IDictionary, and IDictionaryEnumerator and their generic equivalents.
· Using generic collection classes provides increased type-safety and in some cases can provide better performance, especially when storing value types.
Example of Generic Collection:-
using System;
using System.Collections.Generic;
public class Customer
{
public Customer(int id, string name)
{
ID = id;
Name = name;
}
private int m_id;
public int ID
{
get { return m_id; }
set { m_id = value; }
}
private string m_name;
public string Name
{
get { return m_name; }
set { m_name = value; }
}
}
class Program
{
static void Main(string[] args)
{
List myInts = new List ();
myInts.Add(1);
myInts.Add(2);
myInts.Add(3);
for (int i = 0; i
{
Console.WriteLine("MyInts: {0}", myInts[i]);
}
Dictionary customers = new Dictionary ();
Customer cust1 = new Customer(1, "Cust 1");
Customer cust2 = new Customer(2, "Cust 2");
Customer cust3 = new Customer(3, "Cust 3");
customers.Add(cust1.ID, cust1);
customers.Add(cust2.ID, cust2);
customers.Add(cust3.ID, cust3);
foreach (KeyValuePair custKeyVal in customers)
{
Console.WriteLine(
"Customer ID: {0}, Name: {1}",
custKeyVal.Key,
custKeyVal.Value.Name);
}
Console.ReadKey();
}
Whenever coding with the generic collections, add a using System.Collections.Generic declaration to your file.