private class CustomTypeClass
{
    //Console：type name:Int32 isByRef:False
    public void Fun(int value) { }

    //Console：type name:Int32& isByRef:True elementType:Int32
    public void Fun(ref int value) { }

    //Console：type name:Object isByRef:False
    public void Fun(object obj) { }

    //Console：type name:Object& isByRef:True elementType:Object
    public void Fun(ref object obj) { }

    //Console：type name:Int32[] isByRef:False
    public void Fun(int[] intarray) { }

    //Console：type name:Int32[]& isByRef:True elementType:Int32[]
    public void Fun(ref int[] intarray) { }
}

static void Main(string[] args)
{
    MethodInfo[] methodInfos = typeof(CustomTypeClass).GetMethods();
    foreach (var methodInfo in methodInfos)
    {
        ParameterInfo[] parameters = methodInfo.GetParameters();
        foreach (var parameter in parameters)
        {
            var parameterType = parameter.ParameterType;

            Debug.WriteLine(string.Format("method name:{0}", methodInfo.Name));

            LogType(parameterType);
        }
    }
}

private static void LogType(Type type)
{
    if (type.IsByRef)
    {
        Debug.WriteLine(string.Format("type name:{0} isByRef:{1} elementType:{2}", type.Name, type.IsByRef, type.GetElementType().Name));
    }
    else
    {
        Debug.WriteLine(string.Format("type name:{0} isByRef:{1}", type.Name, type.IsByRef));
    }
}