The keyword new is required on 'B.IsValid' because it hides inherited member 'A.IsValid'

  • Thread starter Thread starter Paul Tomlinson
  • Start date Start date
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Paul Tomlinson

The keyword new is required on 'B.IsValid' because it hides inherited member
'A.IsValid'
All I have a couple of classes which resemble (sort of!) this:

public class A
{
public bool bIsValid = true;

public bool IsValid
{
get{ return bIsValid; }
}
}


public class B : A
{
public bool bIsValid = false

public bool IsValid
{
get{ return bIsValid; }
}
}

Now whenever I call IsValid on an object of type A I always want to get
"true" returned, and likewise for an object of type B I always want to get
"false" returned.

How can I acheive this and get rid of this warning at the same time?

Thanks
MA
 
Paul Tomlinson said:
The keyword new is required on 'B.IsValid' because it hides inherited
member 'A.IsValid'
All I have a couple of classes which resemble (sort of!) this:

public class A
{
public bool bIsValid = true;

public bool IsValid
{
get{ return bIsValid; }
}
}


public class B : A
{
public bool bIsValid = false

public bool IsValid
{
get{ return bIsValid; }
}
}

Now whenever I call IsValid on an object of type A I always want to get
"true" returned, and likewise for an object of type B I always want to get
"false" returned.

How can I acheive this and get rid of this warning at the same time?

Thanks
MA
Click to expand...

This is basic inheritence, so you need to "override" the IsValid method
defined in class A in class B if you want it to act differently in the
inherited class, e.g:

public class A
{
public bool IsValid
{
get { return true; }
}
}

public class B : A
{
public override bool IsValid
{
get { return false; }
}
}
 
Jako Menkveld said:
This is basic inheritence, so you need to "override" the IsValid method
defined in class A in class B if you want it to act differently in the
inherited class, e.g:

public class A
{
public bool IsValid
{
get { return true; }
}
}

public class B : A
{
public override bool IsValid
{
get { return false; }
}
}
Click to expand...

Oh, just remembered, you have to mark A.IsValid as virtual, otherwise you
will get a compiler error:

e.g. In class A
public virtual bool IsValid
{
....
}

The virtual keyword tells the compiler that the method can be overriden by
subclasses.
 
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