Invoking Member of a class using Class Name and Method Name

Question

I am trying to invoke function of a class using Reflection (assuming that object initialization as no dependency on Function to be invoked) like this

Answer 1

To answer you query on dynamic; no, that wouldn't be a good fit here. dynamic is useful when the member-name (or operation) is known at compile-time, but is not provable to exist - basically, duck-typing. For example:

dynamic foo = GetSomeRandomObject();
foo.ThisShouldExist("abc");

this does similar things, but the usage is different. So yes, you're left with reflection. What you are doing is pretty-much right. The only thing I might change would be to obtain the MethodInfo, and work from there - although if you can change the API to accept a single string assemblyQualifiedName it would be more convenient and flexible. But perhaps:

public static string InvokeStringMethod5(string assemblyName,
    string namespaceName, string typeName, string methodName, string stringParam)
{
    string assemblyQualifiedName = string.Format("{0}.{1},{2}",
        namespaceName, typeName, assemblyName);
    Type calledType = Type.GetType(assemblyQualifiedName);
    if(calledType == null) throw new InvalidOperationException(
        assemblyQualifiedName + " not found");
    MethodInfo method = calledType.GetMethod(methodName,
        BindingFlags.Public | BindingFlags.Static);
    switch (method.GetParameters().Length)
    {
        case 0:
            return (string)method.Invoke(null, null);
        case 1:
            return (string)method.Invoke(null, new object[] { stringParam });
        default:
            throw new NotSupportedException(methodName
                + " must have 0 or 1 parameter only");
    }
}

Answer 2

To answer the question on how to cast the result to a generic return type, the method would look something like:

public static T InvokeMethod<T>(string assemblyName, string namespaceName, string typeName, string methodName, string stringParam)
{
    // instead of String s = null;
    T methodResult = default(T);

    // instead of s = (String)calledType.InvokeMember(...)
    methodResult = (T)calledType.InvokeMember(...);

    // return s;
    return methodResult;
}