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c#mysqlauthenticationdatareaderread-data

Get Value of specific Column while Login (C# Mysql)


I am trying to make a login at the moment. I watched some videos and found a good way. Every user has an id, Username and Password. I want to get the id of the user who has just been logged in and save it in an Integer. I also tried it with an ExecuteReader but I get an Exception(MySql.Data.MySqlClient.MySqlException).

My current Code is:

 try
            {
                if (sqlCon.State == ConnectionState.Closed)
                {
                    sqlCon.Open();
                }
                string query = "SELECT COUNT(1) FROM Users_Table WHERE Username=@Username AND Password=@Password;";
                MySqlCommand sqlCmd = new MySqlCommand(query, sqlCon);
                sqlCmd.Parameters.AddWithValue("@Username", maintxtbox1.Text);
                sqlCmd.Parameters.AddWithValue("@Password", Hashed_Password);
                int count = Convert.ToInt32(sqlCmd.ExecuteScalar());
                if (count == 1)
                {
                    //Login correct
                }
                else
                {
                    //Login incorrect
                }
            }
            catch
            {
                //Exception
            }
            finally
            {
                sqlCon.Close();
            }

The try with the ExecuteReader:

try
            {
                if (sqlCon.State == ConnectionState.Closed)
                {
                    sqlCon.Open();
                }
                string query = "SELECT id,Username,Password FROM Users_Table WHERE Username=@Username AND Password=@Password;";
                MySqlCommand sqlCmd = new MySqlCommand(query, sqlCon);
                sqlCmd.Parameters.AddWithValue("@Username", maintxtbox1.Text);
                sqlCmd.Parameters.AddWithValue("@Password", Hashed_Password);

                MySqlDataReader datareader = sqlCmd.ExecuteReader();

                if (datareader.HasRows)
                {
                    MessageBox.Show("Test: " + datareader.GetString("id"));
                }
                else
                {
                    //Login incorrect
                }
            }
            catch
            {
                //Exception
            }
            finally
            {
                sqlCon.Close();
            }

I hope somebody can help me. Thank you in advance.


Solution

  • I found a solution to my Question by myself. I forgot the while(datareader.Read()) in the ìf(datareader.HasRows) query. Here is my working Code:

    try
                {
                    if (sqlCon.State == ConnectionState.Closed)
                    {
                        sqlCon.Open();
                    }
                    string query = "SELECT * FROM Users_Table WHERE username=@Username AND password=@Password;";
                    MySqlCommand sqlCmd = new MySqlCommand(query, sqlCon);
                    sqlCmd.Parameters.AddWithValue("@Username", maintxtbox1.Text);
                    sqlCmd.Parameters.AddWithValue("@Password", Hashed_Password);
                    MySqlDataReader datareader = sqlCmd.ExecuteReader();
                    if (datareader.HasRows)
                    {
                        while (datareader.Read())
                        {
                            UserID = datareader.GetInt32("id");
                        }
                    }
                    else
                    {
                        //Incorrect Password
                    }
    
                }
                catch
                {
                    //Error
                }
                finally
                {
                    sqlCon.Close();
                }