Type.GetMethod with Generic method

08-02-05, 05:20 AM

Paul Welter

I'm trying to get a method using Type.GetMethod. There are two methods with
that same name, one is a standard method, the other is a Generic method.
How do I get the Generic method? Is there a BindingFlag that will only get
the Generic one? Here is an example ...

[TestClass()]
public class UserTest
{
public ArrayList GetCollection()
{ return new ArrayList(); }

public List<T> GetCollection<T>()
{ return new List<T>(); }

[TestMethod()]
public void GetCollectionTest()
{
Type genType = typeof(UserTest);
MethodInfo info = genType.GetMethod("GetCollection");
MethodInfo genInfo = info.MakeGenericMethod(typeof(User));
object obj = genInfo.Invoke(this, null);
List<User> users = obj as List<User>;
}
}

If I run this code, I get an AmbiguousMatchException. If I remove the first
GetCollection, it works. Any ideas?

thanks
~ Paul

08-02-05, 06:10 AM

realfun

I haven't read through the c#2.0 spes, but i notice that GetCollection
and GetCollect<T> have the same signature, only differ by return type,
is it a confliction?

08-02-05, 06:44 AM

Jon Shemitz

Paul Welter wrote:

> I'm trying to get a method using Type.GetMethod. There are two methods with
> that same name, one is a standard method, the other is a Generic method.
> How do I get the Generic method? Is there a BindingFlag that will only get
> the Generic one? Here is an example ...

I don't think there's a GetMethod overload that will distinguish your
GetCollection() from your GetCollection<T>() - so far as I can see,
you'll have to call GetMethods(), then filter by Name and
ContainsGenericParameters.

08-02-05, 10:16 AM

Oliver Sturm

Paul Welter wrote:

[..]
> Type genType = typeof(UserTest);
> MethodInfo info = genType.GetMethod("GetCollection");
> MethodInfo genInfo = info.MakeGenericMethod(typeof(User));
> object obj = genInfo.Invoke(this, null);
> List<User> users = obj as List<User>;
> }
> }
>
> If I run this code, I get an AmbiguousMatchException. If I remove the first
> GetCollection, it works. Any ideas?

You might be able to GetMethod("GetCollection<>"), because it's really
the non-constructed Generic type information you are interested in. I
guess that should suffice for Reflection to make the distinction between
the two methods.

Oliver Sturm

08-02-05, 06:19 PM

Paul Welter

> You might be able to GetMethod("GetCollection<>"), because it's really the
> non-constructed Generic type information you are interested in. I guess
> that should suffice for Reflection to make the distinction between the two
> methods.

GetMethod("GetCollection<>") does not work. The documentation has a note
that says...

"The name parameter cannot include type arguments. For example, the C# code
GetMethod("MyGenericMethod<int>") searches for a method with the text name
"MyGenericMethod<int>", rather than for a method named MyGenericMethod that
has one generic argument of type int."

Of cource it doesn't say how to search for a generic.

thanks
~ Paul

08-02-05, 07:34 PM

Oliver Sturm

Paul Welter wrote:

> GetMethod("GetCollection<>") does not work. The documentation has a note
> that says...
>
> "The name parameter cannot include type arguments. For example, the C# code
> GetMethod("MyGenericMethod<int>") searches for a method with the text name
> "MyGenericMethod<int>", rather than for a method named MyGenericMethod that
> has one generic argument of type int."
>
> Of cource it doesn't say how to search for a generic.

You are right. I confused this with the way you can look at Generic
types for classes, e.g. "Type type = typeof(Collection<>)".

Oliver Sturm

08-03-05, 01:45 AM

Ted Miller

You might be able to use GetMethod("GetCollection`1").

But to figure it out, why not write some code that prints out the names of
all the methods in your class (with Type.GetMethods())?

"Oliver Sturm" <oliver> wrote in message
news:2916
[..]

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