Check card number and pin number correct SQL

Question

How would i using the sql command in visual c# check if the card Number and pin no is correct and if it correct to go to form 2?

Answer 1

Example code to perform something like that assuming the card number and pin are unique pair.

            using (SqlConnection connection = new SqlConnection(connectionString))
            using (SqlCommand command = new SqlCommand("SELECT CardID FROM Cards WHERE CardNumber = @cardNumber AND Pin = @pin", connection))
            {
                SqlParameter parameter = new SqlParameter("@cardNumber", SqlDbType.VarChar);
                parameter.Value = cardNumber;

                command.Parameters.Add(parameter);

                parameter = new SqlParameter("@pin", SqlDbType.Int);
                parameter.Value = pin;

                command.Parameters.Add(parameter);

                connection.Open();
                object value = command.ExecuteScalar();
                connection.Close();

                if (value != null)
                {
                    // there was such an card
                    // do something when valid like show second form
                    form2.ShowDialog();
                }
            }

Answer 2

still got a problem i have used the first box as a combo box and i have filled the combo box with the cardNo from the database. So the program is not liking the

object value = sqlcommandchecklogin.ExecuteScalar();

saying it cant be converted

any help?

Answer 3

Hi Welshy,

Check out this:

            using (SqlConnection connection = new SqlConnection(connectionString))
            using (SqlCommand command = new SqlCommand("SELECT CardNumber FROM [Cards]", connection))
            {
                connection.Open();

                SqlDataReader reader = command.ExecuteReader();

                while (reader.Read())
                    comboBox1.Items.Add(reader[0].ToString());

                connection.Close();
            }

Have a nice day,

---

Leo Liu [MSFT]
MSDN Community Support | Feedback to us

Answer 4

still got a problem i have used the first box as a combo box and i have filled the combo box with the cardNo from the database. So the program is not liking the

object value = sqlcommandchecklogin.ExecuteScalar();

saying it cant be converted

any help?

Can you show the code you've done so the problem is easier to spot?

Answer 5

still got a problem i have used the first box as a combo box and i have filled the combo box with the cardNo from the database. So the program is not liking the

object value = sqlcommandchecklogin.ExecuteScalar();

saying it cant be converted

any help?

Can you show the code you've done so the problem is easier to spot?

Problem Been Solved

Answer 6

use ExcuteReader instedof excuteScalar()

then the error will rectifies

---

murali