IEnumerable:
We
have create UI, Business Layer and Data Layer. Data Layer return a list, That
list do some manipulation (changes) in
BL. BL to UI this list return IEnumerable<>. Because I (BL
Developer) thought UI Developer unable
to change the value. Security propose we can use IEnumerable, Because
IEnumerable object unable to Add,Remove,ect...
Difference between IEnumerable and List properties
Example List
IEnumerable VS IEnumerator
Ienumerator also unable to Add and remove
ect... Values. But here we can't use lambda expression.
enumerator
is created or after the Reset method
is called, an enumerator is positioned before the first element of the
collection, and the first call to the MoveNextmethod moves the enumerator
over the first element of the collection.
If MoveNext passes
the end of the collection, the enumerator is positioned after the last element
in the collection and MoveNext returns false. When the enumerator is at this position, subsequent calls
to MoveNext also return false until Reset is
called.
An
enumerator remains valid as long as the collection remains unchanged. If
changes are made to the collection, such as adding, modifying, or deleting
elements, the enumerator is irrecoverably invalidated and the next call
to MoveNext or Reset throws
an InvalidOperationException.
Code :
using Generic.Code;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace Collection.Sample
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Btn_IList_Click(object sender, EventArgs e)
{
CollectionAll obj = new CollectionAll();
IEnumerable<ProEmp> objreturn = obj.RetIEnumerableValue();
var tt= objreturn.AsParallel();
objreturn.Where(n=>n.Id == 103);
var item1 = (objreturn.Where(n => n.Id ==
102)).FirstOrDefault();
MessageBox.Show("Id = " + item1.Id + " Name
= " + item1.Name);
}
private void btnList_Click(object sender, EventArgs e)
{
CollectionAll obj = new CollectionAll();
List<ProEmp> objreturn = obj.RetListValue();
objreturn.Where(n => n.Id ==
103);
var tt = objreturn.Where(n => n.Id == 102);
}
private void btn_IEnumerator_Click(object sender, EventArgs e)
{
CollectionAll obj = new CollectionAll();
IEnumerator<ProEmp> objreturn = obj.RetIEnumeratorValue();
while (objreturn.MoveNext())
{
ProEmp item = objreturn.Current;
MessageBox.Show("Id = " + item.Id + " Name
= " + item.Name);
if (item.Id == 103)
break;
}
MessageBox.Show("While loop
End");
objreturn.MoveNext();
ProEmp item1= objreturn.Current;
MessageBox.Show("Id = " + item1.Id + " Name
= " + item1.Name);
}
private void btnDelegates_Click(object sender, EventArgs e)
{
CollectionAll obj = new CollectionAll();
MessageBox.Show(obj.Calc(15, 8).ToString());
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Generic.Code
{
public class CollectionAll
{
List<ProEmp> objemp;
public IEnumerable<ProEmp> RetIEnumerableValue()
{
Setvalue();
return objemp;
}
public List<ProEmp> RetListValue()
{
Setvalue();
return objemp;
}
public IEnumerator<ProEmp> RetIEnumeratorValue()
{
Setvalue();
return objemp.GetEnumerator();
}
private void Setvalue()
{
objemp = new List<ProEmp>();
ProEmp obj = new ProEmp();
obj.Id = 101;
obj.Name = "Sriram";
obj.Salary = 20000;
obj.Address = "Chennai";
objemp.Add(obj);
obj = new ProEmp();
obj.Id = 102;
obj.Name = "Bala";
obj.Salary = 200000;
obj.Address = "Chennai";
objemp.Add(obj);
obj = new ProEmp();
obj.Id = 103;
obj.Name = "Azeez";
obj.Salary = 150000;
obj.Address = "Madurai";
objemp.Add(obj);
obj = new ProEmp();
obj.Id = 104;
obj.Name = "Ratheesh";
obj.Salary = 200000;
obj.Address = "Madurai";
objemp.Add(obj);
obj = new ProEmp();
obj.Id = 105;
obj.Name = "Vikash";
obj.Salary = 180000;
obj.Address = "Chennai";
objemp.Add(obj);
}
}
}
namespace Generic.Code
{
public class ProEmp
{
public int Id { get; set; }
public string Name { get; set; }
public double Salary { get; set; }
public string Address { get; set; }
}
}
