Does a class implement an interface?

  • Thread starter Thread starter Peter Morris
  • Start date Start date
P

Peter Morris

interface Interface1
{
}

interface Interface2 : Interface1
{
}

class A : Interface2
{
}


static void Main(string[] args)
{
Console.WriteLine(typeof(A).IsSubclassOf(typeof(Interface1)).ToString());
Console.WriteLine(typeof(A).IsSubclassOf(typeof(Interface2)).ToString());
Console.ReadLine();
}


Both return False. Given a type what is the simplest way of checking if it
implements Interface1 either directly, or by implementing Interface2?
 
Peter said:
Both return False. Given a type what is the simplest way of checking
if it implements Interface1 either directly, or by implementing
Interface2?
Click to expand...

How about GetInterface(), e.g.

static void Main(string[] args)
{
Console.WriteLine(typeof(A).GetInterface("Interface1").Name ==
typeof(Interface1).Name);
Console.ReadLine();
}
 
Console.WriteLine(typeof(A).IsAssignableFrom(typeof(Interface1)).ToString());
Console.WriteLine(typeof(A).IsAssignableFrom(typeof(Interface2)).ToString());
Console.ReadLine();

OUTPUT:
False
False

Any other ideas?
 
Obvious when you know how!

typeof(IInterface1).IsAssignableFrom(typeof(A));

If A implements IInterface1 then it means A can be assigned to IInterface1,
not that IInterface1 can be assigned to A!
 
Peter said:
Console.WriteLine(typeof(A).IsAssignableFrom(typeof(Interface1)).ToString());
Console.WriteLine(typeof(A).IsAssignableFrom(typeof(Interface2)).ToString());
Console.ReadLine();
OUTPUT:
False
False

Any other ideas?
Click to expand...

Turn the logic around, the interface is assignable from the class (upcast)
but the reverse (downcast) is not true.
 
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