Working with Generics:
Most
of the classes of System.Collection hold the element as object type. Generics
are more specialized collections classes which are used to group the specified
type of elements. Generics are type-safe container classes that can only operate
on a particular type of data. System.Collections.Generics namespace is
introduced in the .net 2.0 version. Most commonly used collections classes are
ArrayList and Hashtable and their equivalent Generic types are List and Dictionary.
Working with List:
List<string> Products = new
List<string>();
ADD():
Is used to add elements to the
generic collection.
List<string> Products = new
List<string>();
Products.Add("FM Transmitter");
Products.Add("DJ Cable");
Products.Add("Adapter");
AddRange():
Is used to add a specified
range of elements to array.
List<string>
Products = new List<string>();
string[] products = { "FM Transmitter ", "DJ Cable ", "
Adapter " };
Products.AddRange(products);
BinarySearch():
Is used to search entire collection.
Products.BinarySearch("FM Transmitter ") returns index value as 0.
Contains():
Is used to determine whether an
element is in the Collection.
Products.Contains("DJ
Cable").
CopyTo():
copies entire list to the specified array,
starting at the beginning of the target array.
string[ ] products = {“FM Transmitter ", "DJ
Cable ", “Adapter " };
Products.AddRange(products);
string[ ] b = new string[3];
Products.CopyTo(b);
GetRange():
GetRange method is used to
extract the range of elements or to create a new collection of elements from an
existing list.
string[,] c = new string[2,2] { {"hello","hi"},{"hello","hi"} };
Products.Add(c);
foreach (string
[,]f in list.GetRange(0, 1))
{
Console.WriteLine("{0}.{1}",f[0,0],f[0,1]);
}
Indexof():
Is used to find the index of an element in the List.
Products.IndexOf("
Adapter"); returns the zero based index value as 2.
Insert():
Is used to add an element
at a
specified index.
List<string> Products = new
List<string>();
Products.Insert(0,"HeadPhone");
InsertRange():
Is used to add a specified
range of items to list at a specified index:
string[ ] products = {“FM Transmitter ", "DJ
Cable ", “Adapter " };
Products.AddRange(products);
Products.InsertRange (0, products);
Remove:
Is used to remove an item from
the list depending on the given string value.
List<string> Products = new
List<string>();
Products.Add("FM Transmitter");
Products.Add("DJ Cable");
Products.Add("Adapter");s
Products.Remove("Adapter");
RemoveAt:
Is used to remove an element
from the list at a specified index:
List<string> Products = new
List<string>();
Products.Add("FM
Transmitter");
Products.Add("DJ
Cable");
Products.Add("Adapter");
Products.RemoveAt(0)
Sort()
and Reverse():
Is used to sort and reverse the Products.
List<string> Products = new
List<string>();
Products.Add("FM
Transmitter");
Products.Add("DJ
Cable");
Products.Add("Adapter");
Products.Sort();
Products.Reverse();
Using
List to maintain product objects:
For example consider u have an products class
as follows, u can work with it by using
List class as follows:
public class products
{
private string id,
name, price;
// constructor
public products()
{
}
public products(string
_id, string _name, string
_price)
{
id = _id;
name = _name;
price = _price;
}
public string ID
{
get
{
return id;
}
set
{
id = value;
}
}
public string Name
{
get
{
return name;
}
set
{
name = value;
}
}
public string Price
{
get
{
return price;
}
set
{
price = value;
}
}
}
Using List
AddRange Method():
List<products> prdts = new
List<products>();
prdts.AddRange(new products[] { new products("FMT",
"FM Transmitter", "$43"), new
products("DJC",
"DJ Cable", "$54") });
Using
List Add Method():
List<products> prdts = new
List<products>();
prdts.Add(new products("FMT", "FM
Transmitter", "$43"));
prdts.Add(new products("DJC", "DJ
Cable", "$54"));
Iterating through the object in the
collection:
foreach (products
p in prdts)
{
Console.WriteLine("{0}{1}{2}", p.ID,p.Name,p.Price);
}
Working with Dicitionary:
Dicitionary class is one of the effective collection classes
available in the Sytsem.Collections namespace. Out of all available classes
ArrayList and Dicitionary are used more frequently. Apart from all the
collection classes Dicitionary has got one additional feature, i.e., it allows
to store the element with a unique key value. Dicitionary allows to store the
elements as key value pairs. Dicitionary organize the element based on the hash
code of the key.
Common Methods used
in Dicitionary:
Add():
Is used to add elements to the Dicitionary, with a
unique key as follows. We can assign the productid with collections of
products.
Insert elements
into Dicitionary:
Dictionary<string, string>
Products = new Dictionary<string, string>();
Products.Add("FT", "FM Transmitter");
Products.Add("DC", "DJCable");
Products.Add("Ad", "Power Adapter");
Remove():
Is used
to remove the element with specified key from the Dictionary.
Dictionary<string, string>
Products = new Dictionary<string, string>();
Products.Add("FT", "FM Transmitter");
Products.Add("DC", "DJCable");
Products.Add("Ad", "Power Adapter");
Console.WriteLine("Before the element is removed");
foreach (DictionaryEntry s in Products)
{
Console.WriteLine("Product ID:{0}\t Product Name:{1}",
s.Key, s.Value);
}
Products.Remove("Ad");
Console.WriteLine("====================");
Console.WriteLine("After the element is removed");
foreach (DictionaryEntry s in Products)
{
Console.WriteLine("Product ID:{0}\t Product Name:{1}",
s.Key, s.Value);
}
Contains() and
Containskey():
Returns a boolean value which is used to determine whether
the dicitionary contains the specified key.
Dictionary<string, string>
Products = new Dictionary<string, string>();
Products.Add("FT",
"FM Transmitter");
Products.Add("DC",
"DJCable");
Products.Add("Ad",
"Power Adapter");
Console.WriteLine("{0}", Products.Contains<string>("Ad")); Console.WriteLine("{0}", Products.ContainsKey("Ad"));
ContainsValue():
Returns a boolean value which is used to determine whether
the dictionary contains the specified value.
Dictionary<string, string>
Products = new Dictionary<string, string>();
Products.Add("FT",
"FM Transmitter");
Products.Add("DC",
"DJCable");
Products.Add("Ad",
"Power Adapter");
Console.WriteLine("{0}", Products.ContainsValue("DJCable"));
CopyTo():
Is used to copies entire elements in the dictionary
to an existing one dimensional array.
string[
] products = new string[
3 ];
Dictionary<string, string>
Products = new Dictionary<string, string>();
Products.Add("FT",
"FM Transmitter");
Products.Add("DC",
"DJCable");
Products.Add("Ad",
"Power Adapter");
Products.CopyTo(products, 0);
foreach (string
s in products)
{
Console.WriteLine("{0}",
s);
}
Next:
Working with types in System.IO.
Furhter Reading:
No comments:
Post a Comment