Question

What i’m tring to do is this.

I have a Inheritance tree that looks something like this

BaseType
BaseType : DerType1
BaseType : DerType2
BaseType : DerType3

so first i’ve declare a variable of type BaseType to be used

BaseType b;

Any of the derived types can be read in as a string

so i’ve got an instance creator something like

  object o =  Activator.CreateInstance(Type.GetType(readValue));

What i then want to do is assign this new object to B

Something like

b = o //Doesn't work obviously because of casting rules
b= (DerType1)o; //works 

but i can’t figure out how to dynamically retype the intended cast

b = (o.GetType())o; //what i want but can't be done like this

maybe there’s a trick with using generics i’m not thinking about?

I found an article talking about doing it something like this with generics

public T GetInstance<T>(string type) where T: new()
        {
            return (T)Activator.CreateInstance(Type.GetType(typeName));
        } 

but it seems to me that i still will need to statically reference the type name in the call to this method

b  = GetInstance<DerType1>("DerType1")
b  = GetInstance<DerType2>("DerType2")
b  = GetInstance<DerType3>("DerType3")

thanks for the ideas.

Maybe i should be taking a whole new, better approach?
Also maybe i’m just not paying attention as

b = (BaseType)Activator.CreateInstance(Type.GetType(typeName));

seems to be helpful

Answer 1

Why not just declare:

object o;

as

BaseType o;

Then you could do:

BaseType o =  Activator.CreateInstance(Type.GetType(readValue)) as BaseType;