CODEWITHSUNDEEP
c#reflection
Amit Mittal
Amit Mittal

Reputation: 1127

Working with objects created with Activator.CreateInstance

Consider the code below:

void fun1(string typeName)
{
    object adap = Activator.CreateInstance(typeName);
    adap.dowork(); //won't compile because of strongly typed.
}

Using Activator.CreateInstance() we can easily create instance of any type, but if we don't know the typename at design time, it is not possible downcast it to its actual type either.

My question is, how can we call a function of instance created by Activator.CreateInstance if we cant downcast it to its appropriate type as we dont know the typename at design time, but we know that the function exists.

I hope I've made myself clear.

Upvotes: 2

Views: 1321

Answers (3)

mehrandvd
mehrandvd

Reputation: 9116

If you know that typeName has the method doWork, it would be better that your type implements an interface like:

interface IDoWorkSupport
{
    void DorWork();
}

then you can make your code like:

var adap = (IDoWorkSupport) Activator.CreateInstance(typeName);
adap.DoWork(); //this now compiles

In this case its a more object-oriented solution.

Upvotes: 0

Joseph Gabriel
Joseph Gabriel

Reputation: 8510

One thing you can do is assign it to a dynamic type.

dynamic adap = Activator.CreateInstance(typeName);
adap.dowork(); //this now compiles

It is also possible to invoke a method dynamically using reflection if you know the method name.

Upvotes: 6

Marc Gravell
Marc Gravell

Reputation: 1062770

The best option is to know some common interface or base-class, and cast to that. However, if that is not possible you can duck-type by using 

dynamic adap = ...

And the rest of your code as-is.

If that isn't possible (wrong .net version etc) then you'll have to use reflection.

Upvotes: 3

Related Questions