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I am trying to create a quiz in c# using forms and a database. I am currently struggling with comparing the input into a textbox with the correct answer which is in the database.
For example: If I input 'A' in the textbox for the answer and the correct answer stored in the database was 'A' it would add one to the score.

The code I have used for this (which doesn't work) is below:

SqlConnection con = new SqlConnection(conn);
 SqlCommand cmd = new SqlCommand("select Answer from Questions where QuestionID=3", con);
 cmd.Parameters.AddWithValue("@Answer", InputAnswerTxt.Text);

 con.Open();
 SqlDataAdapter adpt = new SqlDataAdapter(cmd);
 DataSet ds = new DataSet();
 adpt.Fill(ds);
 using (SqlDataReader re = cmd.ExecuteReader())
 
 if (re.Read())
 
 string AnswerSelection = (string)re["Answer"];
 SetScore = SetScore++;

 
 MessageBox.Show("Your score is : " + SetScore);

 
 con.Close();

Any suggestions at all would be helpful! If you need to see some more of where the code is embedded please do let me know.

If you can provide your database schema it might help. Since you have the user's answer in memory (not in DB) You might not need to attach it as a parameter to the SQL command. You should be able to just pull down the answer to the question your want (looks like where questionID=3) then compare InputAnswerTxt.Text with what the DB returns. Then count up your score if they are equal to each other.

More of your code my need to be posted (IE where some of these variables are defined, and the DB schema, etc) to give further advice.

I am assuming the number of quiz questions you have are in 100s at best and not in 1000000+s. So, rather than going to the database every time you receive an answer, you should grab all the question Id and their correct answer right in the beginning and store it in a dictionary. Then check the dictionary for correctness and update the score.

Below is a rough guideline, it's not an entirely working code, but that should give you a good enough idea, hopefully, else ask in the comment.

So in your constructor, you could make a call to retrieve all the answers. Like below:

 private Dictionary<string, string> _correctAnswerLookup;
 public Form1()
 
 InitializeComponent();
 _correctAnswerLookup = GetCorrectAnswerByQuestionLookup();
 

 private Dictionary<string, string> GetCorrectAnswerByQuestionLookup()
 
 Dictionary<string, string> correctAnswerLookup = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
 using (SqlConnection connection = new SqlConnection(connectionString))
 
 SqlCommand cmd = new SqlCommand("select QuestionId, Answer from Questions", connection);
 try
 
 connection.Open();
 var reader = cmd.ExecuteReader();
 while (reader.Read())
 
 string questionId = (string)reader["QuestionId"];
 string answer = (string)reader["Answer"];
 if (!correctAnswerLookup.ContainsKey(questionId))
 
 correctAnswerLookup.Add(questionId, answer);
 
 
 
 catch (Exception e)
 
 // your exception handling
 
 
 return correctAnswerLookup;
 

And on your answer received event, you could just check the lookup and update the score. Handle the subtleties about validation and null check etc yourself.

 private void OnAnswerSubmitted()
 
 string currentQuestionId = ""; // however you get this in your UI.
 string selectedAnswer = "";

 if (_correctAnswerLookup[currentQuestionId] == selectedAnswer)
 
 scoreCounter++;
 

 lblScoreCounter.Text = scoreCounter.ToString();