GetEnumerator () what is the use of the

amigo1 · November 8th, 2012, 01:30 AM

what is the use of the GetEnumerator (). For example if I write a small code as

Code:

using System;  using System.Collections;
class MyClass : IEnumerator, IEnumerable {
int[] intst = { 1,2,3,4 };
int idx = -1;

public IEnumerator GetEnumerator() {
return this; //-------------------------------------------------------------->>>>>>>>>>>
}
// to implement IEnumerator.

public object Current {
get {
return intst[idx]; //--------------------------------------------------->>>>>>>>>>>>>>>
}
}
// Advance to the next object.
public bool MoveNext() {
if(idx == intst.Length-1) {
Reset(); 
return false;
}
idx++;
return true;
}

public void Reset() { idx = -1; }
}
class Enumer {
static void Main() {
MyClass mc = new MyClass();
// To display the contents of mc.
foreach(int i1 in mc)
Console.Write(i1 + " ");
Console.WriteLine();

}
}
Here is the output:
1 2 3 4

Here see the lines with multiple arrowheads. T he second one I can able to follow that it returns the current object
at idx ------- What i do not follow is the FIRST arrow headed code line

"
public IEnumerator GetEnumerator() {
return this;
"

---------- what is the use of it i mean?

ChristianNagel · November 28th, 2012, 03:55 AM

Quote:

Originally Posted by amigo1

what is the use of the GetEnumerator (). For example if I write a small code as

Code:

using System;  using System.Collections;
class MyClass : IEnumerator, IEnumerable {
int[] intst = { 1,2,3,4 };
int idx = -1;

public IEnumerator GetEnumerator() {
return this; //-------------------------------------------------------------->>>>>>>>>>>
}
// to implement IEnumerator.

public object Current {
get {
return intst[idx]; //--------------------------------------------------->>>>>>>>>>>>>>>
}
}
// Advance to the next object.
public bool MoveNext() {
if(idx == intst.Length-1) {
Reset(); 
return false;
}
idx++;
return true;
}

public void Reset() { idx = -1; }
}
class Enumer {
static void Main() {
MyClass mc = new MyClass();
// To display the contents of mc.
foreach(int i1 in mc)
Console.Write(i1 + " ");
Console.WriteLine();

}
}
Here is the output:
1 2 3 4

Here see the lines with multiple arrowheads. T he second one I can able to follow that it returns the current object
at idx ------- What i do not follow is the FIRST arrow headed code line

"
public IEnumerator GetEnumerator() {
return this;
"

---------- what is the use of it i mean?

The GetEnumerator method is defined by the interface IEnumerable. This method needs to return an object that implements the IEnumerator interface. In this case the class MyClass implements both IEnumerable and IEnumerator, that's why the GetEnumerator method can return the instance that implements IEnumerator, which is "this".
The caller of this method (the foreach statement) can access the members of the interface IEnumerator, such as MoveNext and Current which are implemented by MyClass.

amigo1 · November 30th, 2012, 02:25 AM

thank you teacher
regards
amigo1