CODEWITHSUNDEEP
c#.net
user2071747
user2071747

Reputation: 201

Declaration variable with type in variable of type 'Type'

I have variable in my class with type of 'Type':

class A
{
    public static Type MyType;
}

And I declared this variable with anywhere construction. Example:

A.MyType = b.GetType();

First problem: I need declare new variable with type stored in MyType.

<MyType> myValue = new <MyType>;

Second problem: I need a function that indicates whether reducible to each other variables of the 'Type'.

Upvotes: 2

Views: 3593

Answers (1)

Jon Skeet
Jon Skeet

Reputation: 1504162

First problem: I need declare new variable with type stored in MyType.

You can't do this, basically.

Variable types need to be known at compile-time. You can't declare a variable using a type which is only known at execution time. You can get some of the way there using generics:

public class Foo<T>
{
    private T value;
}

You can even add a constraint to require that T has a parameterless constructor which you can then call:

public class Foo<T> : new()
{
    private T value = new T();
}

... and you could create a Foo<T> when you only know the type of T at execution time using reflection:

Type genericDefinition = typeof(Foo<>);
Type constructed = genericDefinition.MakeGenericType(A.MyType);
object instance = Activator.CreateInstance(constructed);

... but it will get messy pretty quickly. You haven't told us anything about what you're actually trying to achieve, so it's hard to suggest an alternative - but if you can possibly redesign to avoid this, I would.

Second problem: I need a function that indicates whether reducible to each other variables of the 'Type'

It's possible that you're looking for Type.IsAssignableFrom, but it's not clear...

Upvotes: 8

Related Questions