C# – WCF. Service generic methods

cgenericswcf

How can I use generic methods in wcf service?

I wrote this code:

[OperationContract]
void AddItem<T>(T item);

But I receive the following Error:

Type 'T' cannot be exported as a schema type because it is an open generic type. You can only export a generic type if all its generic parameter types are actual types.

Best Answer

You simply can't. It's not possible to do that, as soap does not support this. See this article, which mentions how to get around generics, by creating an intermediate local object that is called and casts the object before calling the WCF operation.

Related Solutions

C# – Create Generic method constraining T to an Enum

Since Enum Type implements IConvertible interface, a better implementation should be something like this:

public T GetEnumFromString<T>(string value) where T : struct, IConvertible
{
   if (!typeof(T).IsEnum) 
   {
      throw new ArgumentException("T must be an enumerated type");
   }

   //...
}

This will still permit passing of value types implementing IConvertible. The chances are rare though.

C# – How to use reflection to call a generic method

You need to use reflection to get the method to start with, then "construct" it by supplying type arguments with MakeGenericMethod:

MethodInfo method = typeof(Sample).GetMethod(nameof(Sample.GenericMethod));
MethodInfo generic = method.MakeGenericMethod(myType);
generic.Invoke(this, null);

For a static method, pass null as the first argument to Invoke. That's nothing to do with generic methods - it's just normal reflection.

As noted, a lot of this is simpler as of C# 4 using dynamic - if you can use type inference, of course. It doesn't help in cases where type inference isn't available, such as the exact example in the question.

Best Answer

Related Solutions

C# – Create Generic method constraining T to an Enum

C# – How to use reflection to call a generic method

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