Create Login Form on C#

Kamil Zahid

Hi Guys

This is the code i have used on C# to create a login form and it always prompts me with "Invalid username or password" even though my database holds the correct username and password. Please help???

private void button1_Click(object sender, EventArgs e)
        {
            string username = textBox1.Text;
            string password = textBox2.Text;

            if (ValidateUserNamePassword(username, password))
            {
                MessageBox.Show("Login successful");

            }
            else
            {
                MessageBox.Show("Invalid user name or password");
                return;
            }
        }

        public bool ValidateUserNamePassword(string username, string password)
        {

            MySqlConnection cn = new MySqlConnection(@"SERVER=localhost;" + "DATABASE=clientmanagement;" + "UID=root;" + "PASSWORD=qwerty;");
            {
                MySqlCommand cmd = new MySqlCommand();
                cmd.Connection = cn;
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.CommandText = "tsp_GetUserNameAndPassword";

                MySqlParameterCollection sqlParams = cmd.Parameters;
                sqlParams.AddWithValue("@UserName", username);
                sqlParams.AddWithValue("@Password", password);

                cn.Open();
                MySqlDataReader dr = cmd.ExecuteReader(CommandBehavior.SingleRow);
                if (dr.Read())
                {
                    // this will return true if a row matching the username and password is found.
                    // this means that the user's input is valid
                    return true;
                }
                else
                {
                    return false;
                }

                dr.Close();
                cn.Close();

            }
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}

7 Replies

Know the answer? Post it — somebody with the same question will find it here.

piyush sardhara15y ago
nidhi write code propely
Nidhi Shah15y ago
SqlConnection

con.Open();
cmd.ExecuteNonQuery();
da.Fill(ds);
con.Close();

con = new SqlConnection(strConn);string strCmd = "select UserName, Password from Login where UserName='" + txtUserName.Text + "' and Password ='" + txtPassword.Text + "'";SqlCommand cmd = new SqlCommand(strCmd, con);SqlDataAdapter da = new SqlDataAdapter(strCmd, con);DataSet ds = new DataSet();MessageBox.Show("Login successful", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
Suthish Nair15y ago
Vulpes is right...

try...

CREATE DEFINER=`root`@`%` PROCEDURE tsp_GetUserNameAndPassword(
   @username varchar(max),
   @Password varchar(max))
SELECT
   username, password
   FROM login
   WHERE lower(username) = lower(@UserName) AND password = @Password;

Another thing, do you have access to DB?

try...
Vulpes15y ago
I don't use MySql but you're not defining your two parameters in an IN clause within the brackets after the procedure name.

Also, there's no END though I assume this is because you've only posted an extract.

Apart from that, you are returning a row rather than a single value so your code should work.
Kamil Zahid15y ago
This is what i have in mysql editor for the procedure, is it OK?

CREATE DEFINER=`root`@`localhost` PROCEDURE `tsp_GetUserNameAndPassword`()
BEGIN
SELECT
username, password
FROM login
WHERE
username = @UserName AND password = @Password;
Vulpes15y ago
If it is returning a single value (a boolean say) rather than a whole row, then ExecuteScalar() should also work:

bool result = (bool)cmd.ExecuteScalar();
Suthish Nair15y ago
Are you sure your query returns SingleRow only? try, with SingleResult.

Run the sql statement from procedure inside your editor window to check the output.

Put a breakpoint and check the value getting here (dr.Read()).

Also, take care of upper/lower case of characters.