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use of virtual/override on class variables as I can

use of virtual/override on class variables as I can

Kumar Gaurav

11y2.7kVisual Basic .NET

Why can't I use virtual/override on class variables as I can on methods?

Like for example we have 2 classes

class A

{

public virtual int x;

}

class B : A

{

public override int x;

}

when i compile this above code it display error like "The modifier 'virtual' is not valid for this item"???

why display this type of error?? please help me in details .

3 Replies

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Sujeet Suman11y ago
Accepted answer
Gaurav we are using virtual keyword with any class method when we need to extend or override that method in their derived class. Where as a variable is declaration only not implementation. So implementation word for a variable is meaning less.

That's why we are not using virtual/override with a class variable.

If this is helpful for you then please accept my Answer.
0
Kumar Gaurav11y ago
Hi,
We can't override a field means we can't use field as a virtual?
like public virtual int x; we can't declare a variable with virtual ?
0
Priyaranjan K S11y ago
Hi Kumar,

You cannot over ride a field. Instead you can implement it as a method or property as below . Define an initialization method in the base class, override it in the inheriting class, and call it from the base constructor before accessing any fields:

// Base class
public class A
{
protected string x;
public A()
{
ChangeValue();
Console.WriteLine(x);
}
public virtual void ChangeValue()
{
x = "First Assignment";
}
}
// Inheriting class
public class B : A
{
public override void ChangeValue()
{
x = "Second Assignment";
}
}

Thanks,
Priyan

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