An Indexer is a public property of a class that is used to fetch values from a collection contained by class in an efficient & easy way.
Indexer makes a class as a virtual array.
Source Code:
Indexer makes a class as a virtual array.
- this keyword is used to create indexer
- Indexer can be overloaded
- More then one parameters can be used for indexing
Source Code:
public class Student
{
public int RollNo { get; set; }
public string Name { get; set; }
public string Class { get; set; }
}
class Program
{
static void Main(string[] args)
{
school objSchool = new school();
//Class
object used as an array using Indexer
Student obj1 = objSchool[2]; //Indexer1
Student obj2 = objSchool["Ravi"]; //Indexer2
Console.WriteLine("Student Roll
No:{0}, Name:{1}",obj1.RollNo, obj1.Name);
Console.WriteLine("Student Roll
No:{0}, Name:{1}", obj2.RollNo, obj2.Name);
Console.ReadLine();
}
class school
{
private List<Student> lstStudent = new List<Student>();
public school()
{
lstStudent.Add(new Student { RollNo = 1, Name
= "Ram", Class = "5th" });
lstStudent.Add(new Student { RollNo = 2, Name
= "Shiv", Class = "6th" });
lstStudent.Add(new Student { RollNo = 3, Name
= "Ravi", Class = "5th" });
}
public Student this[int rollNo]
{
get
{
return lstStudent.Find(new Predicate<Student>(x => x.RollNo == rollNo));
}
set
{
//lstStudent.Find(new
Predicate<Student>(x => x.RollNo == rollNo)).RollNo = rollNo; //Set can be used but here it does not have meaning
}
}
public Student this[string name]
{
get
{
return lstStudent.Find(new Predicate<Student>(x => x.Name == name));
}
set
{
//lstStudent.Find(new
Predicate<Student>(x => x.Name == name)).Name = name;
}
}
}
}
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