private void Loginbutton_Click_1(object sender, EventArgs e)
{
CONNECT conn = new CONNECT(); //our connection
DataTable table = new DataTable(); //creates our table in the dataset
MySqlDataAdapter adapter = new MySqlDataAdapter(); //creates a link between the datasource and the dataset
MySqlCommand command = new MySqlCommand(); //executes our sql queries etc.
string query = "SELECT * FROM `users` WHERE `username`=@usn AND `password` = @pass"; //@pass and @usn are placeholders
command.Parameters.Add("@usn", MySqlDbType.VarChar).Value = textBoxUsername.Text; //it takes the input from the user and replace its respective placeholder of its type
command.Parameters.Add("@pass", MySqlDbType.VarChar).Value = textBoxPassword.Text;
command.CommandText = query;
command.Connection = conn.GetConnection();
adapter.SelectCommand = command; //the adapter here uses the selectcommand to retrieve data specified in the datasource i.e the database
adapter.Fill(table); // if the value retrieved matches the one at the data source then it fills the table data in the dataset if the table hasn't been created then it creates one.
//if the username and password exists
if (table.Rows.Count > 0) //if the no of rows in the table in the dataset then execute the content within.
{
//show the main form
this.Hide();
Main_Form mForm = new Main_Form();
mForm.Show();
}
else if (textBoxUsername.Text.Trim().Equals(""))
{
MessageBox.Show("Enter a valid username", "Username", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else if (textBoxPassword.Text.Trim().Equals(""))
{
MessageBox.Show("Enter a valid password", "Password", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
MessageBox.Show("Username or Password does not exist", "Incorrect data", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}