ASP.NET

<asp:regularexpressionvalidator id="RegularExpressionValidator1" runat="server" controltovalidate="txtEmail" validationexpression="^\w+[\w-\.]*\@\w+((-\w+)|(\w*))\.[a-z]{2,3}$" errormessage="Please enter an email address in the form xyz@abc.com" xmlns:asp="#unknown"></asp:regularexpressionvalidator>

//Insert to database and display task reference
            try
            {
                conAppDB.Open();
                // Retrieve latest taskID from database and display it.
                //:TODO  Update design, because of possible concurrent users.
                string getTaskRef = @"SELECT MAX([taskID_PK]) FROM [teamwiki].[dbo].[task];";  
                SqlCommand getTaskRefSQL = new SqlCommand(getTaskRef, conAppDB);
                if (getTaskRefSQL != null)
                {
                    txtTaskRef.Text = (string)getTaskRefSQL.ExecuteScalar(); 

// Note: Although the code passes through here, the value of getTaskRefSQL is null, is this a bug?

                }

            }
            catch (InvalidCastException)
            { 
                //Occurs when database is empty.
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally {
                conAppDB.Close();
            }