How to use a Type variable in a generic method call (C#)

Question

I have a Type variable t passed into a method, and I want to use it as a generic parameter when calling IQueryable.Join like the following

Answer 1

Basically you've got to call the method with reflection:

• Get the generic method template with Type.GetMethod
• Call MakeGenericMethod passing in your 4 type parameters
• Invoke the method passing in the regular arguments

It's a pain :(

Answer 2

I'm not sure of the details of your "type variable," but if the variable is already a generic parameter to the method, you can use it as a generic parameter to Join also:

public void MyMethod<T>()
{
    // do some stuff to get queryResult, then
    queryResult.Join<Type1, Type2, T, Type3>(items, outerSelector, innerSelector, (a, b) => something);
}