using System;

public class Program

{

    public static void Main()

    {

        string txtDateOfOccurrence = null;

        DateTime? dateOccurrence = null;

        if (!string.IsNullOrEmpty(txtDateOfOccurrence))

        {

            try

            {

                dateOccurrence = DateTime.Parse(txtDateOfOccurrence);

                Console.WriteLine(dateOccurrence.ToString());

            }

            catch (Exception ex)

            {

                Console.WriteLine("Invalid date of occurrence. Error: " + ex.Message);

            }

        }

        if (dateOccurrence != null)

        {

            Console.WriteLine("yay!");

        }

        else

        {

            Console.WriteLine("null!");

        }

        //what it needs to do with database

        //if (dateOccurrence != null)

        //{

        //  cmd.Parameters.AddWithValue("@dateOccur", dateOccurrence);

        //}

        //else

        //{

        //  cmd.Parameters.AddWithValue("@dateOccur", null);

        //}

        //

        // what happens: Error: The parameterized query 'blah' expects the parameter '@dateOccur', which was not supplied.

    }

}