Change from CommandType.StoredProcedure to CommandType.Text;

public Product GetProduct(int ID)
{
            SqlConnection con = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand("GetProductByID", con);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@ProductID", ID);

            try
            {
                con.Open();
                SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SingleRow);
                if (reader.Read())
                {
                    Product product = new Product((string)reader["ProductName"],
                                                  (decimal)reader["UnitPrice"]);
                    return (product);
                }
                else
                {
                    return null;
                }
            }
            finally
            {
                con.Close();
            }
}

    public class Product
    {
        public string ProductName { get; set; }
        public decimal UnitPrice { get; set; }      

        public Product(string productName, decimal unitPrice)
        {
            ProductName = productName;
            UnitPrice = unitPrice;
        }
    }

With its Stored Procedure as such:

USE [Northwind]
GO
/****** Object:  StoredProcedure [dbo].[GetProductByID]    Script Date: 07/28/2013 16:18:34 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[GetProductByID] @ProductID nchar(5)
AS
SELECT ProductName, UnitPrice
FROM Products
WHERE ProductID = @ProductID

However, I do not want to depend on the Stored Procedure and want to input in the Query as text, is that possible? When I replace the above code with below, it shows error connecting to database:

public Product GetProduct(int ID)
{
            SqlConnection con = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = con;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "SELECT ProductName, UnitPrice FROM Products WHERE ProductID = @ProductID";
            SqlParameter parameter1 = cmd.Parameters.Add("@ProductID", SqlDbType.Int);
            parameter1.Direction = ParameterDirection.Input;
          
            try
            {
                con.Open();
                SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SingleRow);
                if (reader.Read())
                {
                    Product product = new Product((string)reader["ProductName"],
                                                  (decimal)reader["UnitPrice"]);
                    return (product);
                }
                else
                {
                    return null;
                }
            }
            finally
            {
                con.Close();
            }
 }

Can anyone points to me where are my mistakes?

thanks.