How to tell if an instance is of a certain Type or any derived types

Question

I\'m trying to write a validation to check that an Object instance can be cast to a variable Type. I have a Type instance for the type of object they need to provide. But th

Answer 1

How about this:

    MyObject myObject = new MyObject();
    Type type = myObject.GetType();

    if(typeof(YourBaseObject).IsAssignableFrom(type))
    {  
       //Do your casting.
       YourBaseObject baseobject = (YourBaseObject)myObject;
    }  

This tells you if that object can be casted to that certain type.

Answer 2

If you are working with Instances, you should be going for Type.IsInstanceOfType

(Returns) true if the current Type is in the inheritance hierarchy of the object represented by o, or if the current Type is an interface that o supports. false if neither of these conditions is the case, or if o is nullNothingnullptra null reference (Nothing in Visual Basic), or if the current Type is an open generic type (that is, ContainsGenericParameters returns true). -- MSDN

        Base b = new Base();
        Derived d = new Derived();
        if (typeof(Base).IsInstanceOfType(b)) 
            Console.WriteLine("b can come in.");    // will be printed
        if (typeof(Base).IsInstanceOfType(d)) 
            Console.WriteLine("d can come in.");    // will be printed

If you are working with Type objects, then you should look at Type.IsAssignableFrom

(Returns) true if c and the current Type represent the same type, or if the current Type is in the inheritance hierarchy of c, or if the current Type is an interface that c implements, or if c is a generic type parameter and the current Type represents one of the constraints of c. false if none of these conditions are true, or if c is nullNothingnullptra null reference (Nothing in Visual Basic). -- MSDN

Answer 3

I think you need to restate your conditions, because if obj is an instance of Derived, it will also be an instance of Base. And typ.IsIstanceOfType(obj) will return true.

class Base { }
class Derived : Base { }

object obj = new Derived();
Type typ = typeof(Base);

type.IsInstanceOfType(obj); // = true
type.IsAssignableFrom(obj.GetType()); // = true