problem faking a method call with ref struct argument

I made simple windows form with 2 button on it, button 1 is to prepare and test, button 2 is to act.

problem 1.
when I click on button 1 and then button 2, it will fake the method, but the passed parameter is not correct. it's the value I used when I was in preparing phase, not the actual value passed to the method, when I do it without using reference parameter passing, everything will be fine. but in my real scenario I have to use reference parameter passing.

problem 2.
when I click button 2 first and then button 1, it will throw an exception that contains:

*** No method calls found in recording block. Please check:
* Are you trying to fake a field instead of a property?
* Are you are trying to fake mscorlib type?

It means that if original method is called once before faking, we can not fake it anymore.

I can handle problem 2 by prevention of calling original method before faking, but I don't know what to do with problem 1.


here is my code:

namespace TypeMocTestAPP
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        
        [TestMethod]
        private void button1_Click(object sender, EventArgs e)
        {
            //Prepare
            var fake = Isolate.Fake.Instance<TestClass>();
            DateEx dateEx = new DateEx { Day = 1, Month = 2, Year = 2000 };
            Isolate.WhenCalled(() => fake.DateToString(ref dateEx)).DoInstead(context =>
            {
                string param0 = ((DateEx)context.Parameters[0]).Year.ToString();
                return "Fake is Called, Year is:" + " " + param0;
            }
            );
            Isolate.Swap.AllInstances<TestClass>().With(fake);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //ACT
            TestClass testClass = new TestClass();
            DateEx refDate = new DateEx() { Year = 1999, Month = 11, Day = 1 };
            MessageBox.Show(testClass.DateToString(ref refDate));
        }

    }

    public struct DateEx
    {
        public int Year;
        public int Month;
        public int Day;
    }

    public class TestClass
    {
        public string DateToString(ref DateEx dateEx)
        {
            return "Original is Called, Year is: " + " " + dateEx.Year.ToString();
        }
    }
}