Not able to pass datetime in ASP.Net MVC 5

I am beginner in software field. And I have problem in passing Datetime to a class constructor. So there is one ASP.Net MVC 5 application and it interacts with VB.net code for backend work. (Humor me on this).

Here is what I have till now.

ViewModel:

public class Add
{
    public DateTime? dateTime { get; set; }
}

Controller:

[HttpPost]
public ActionResult AddLocationBlock(Add viewModel)
{
        if(viewModel.dateTime !=null)
        {
            ClsArgs obj1 = new ClsArgs((viewModel.dateTime);   
                                                     ^^ ERROR: matching constructor not found                                                             
        }    
        return new EmptyResult();
}

VB.net constructor definition:

 public ClsArgs(DateTime ExpirationDate);

Below solution works:

 [HttpPost]
    public ActionResult AddLocationBlock(Add viewModel)
    {
            if(viewModel.dateTime !=null)
            {
                DateTime dte = new DateTime();
                ClsArgs obj1 = new ClsArgs(dte);                                    
            }    
            return new EmptyResult();
    }