Activator.CreateInstance with implicit type conversion

[alp]

Hi,

I've got a class constructor that takes

public Foo(int a, MyString b)

MyString type has an implicit operator for string so I can call this
from code with Foo f = new Foo(1, "hello");

However i'd like to programmatically call the constructor using

Activator.CreateInstance(typeof(Foo), new object[] { 1, "hello" })

This doesn't work because the constructor is of type MyString, and the
CreateInstance Binder is looking for a type string. Is there anyway to
get the Binder to just 'use' the params I pass in, or at least to see
if there is a possible implicit type conversion possible???
Cheers,

Al

 

[Girish Bharadwaj]

You might be able to do that *somewhat* using reflection. Look into
ConstructorInfo class. Is that what you were looking for?

 

[Guest]

Another solution may be subclassing the Binder, and passing this to the
overloaded Activator.CreateInstance that takes Binder param.

 

[Ming Chen]

Hi,
The implicit type conversion is a mechanism supported by C# compiler, not
CLR. So I think that you would have to do it by yourself through reflection.
At least, you would have to data mine whether there is a direct type
conversion constructor for MyString that accepts a string parameter, then
invoke the constructor and get the MyString reference needed for the
reflection call.

Regards
Ming Chen

 

[alp]

Hi,
The implicit type conversion is a mechanism supported by C# compiler, not
CLR. So I think that you would have to do it by yourself through reflection.
At least, you would have to data mine whether there is a direct type
conversion constructor for MyString that accepts a string parameter, then
invoke the constructor and get the MyString reference needed for the
reflection call.

Regards
Ming Chen

Hmm, the problem is that the use of CreateInstance is in a factory
class which i'd like to keep generic rather than use specific mining
through reflection to find an appropriate constructor and
implicit/explicit type conversion routine.

Al

 

[alp]

If I invoke ConstructorInfo.Invoke(object[] args) it fails with the
same error as above, the Binder is looking for the explicit parameter
match

Thanks,
Al

 

[alp]

I've tried this but the Binder class is abstract and the documentation
doesn't tell me which class implements the default Binder so that I
could subclass it. I tried using the Binder implementation given in the
docs and quoted various times on the web, but even with a modified
CanConvert method it fails and i'm concerned that by implementing my
own type rather than subclassing the built-in type I may end up not
implementing all the built-in functionality.

Thanks,
Al