Question

I have code for a quiz but am unsure on how I count the total number of questions in my database. I know that I need a count query but i’m not sure where to insert it.
Here is my code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
using System.Data.Sql;
using System.Data.SqlClient;

namespace Quiz_Test
{
public partial class Form1 : Form
{
public Form1()
{
  InitializeComponent();
}

String chosenAnswer, correctAnswer;
DataTable table;
int questionNumber;

private void Form1_Load(object sender, EventArgs e)
{
  string cnString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\Users\\Hannah\\Desktop\\QuizQuestions.accdb";

  OleDbConnection conGet = new OleDbConnection(cnString);
  OleDbCommand cmdGet = new OleDbCommand();

  conGet.Open();

  cmdGet.CommandType = CommandType.Text;
  cmdGet.Connection = conGet;

  cmdGet.CommandText = "SELECT * FROM QuizQuestions ORDER BY rnd()";

  OleDbDataReader reader = cmdGet.ExecuteReader();
  table = new DataTable();
  table.Load(reader);

  foreach (DataRow row in table.Rows)
  {
    labelQuestion.Text = table.Rows[0]["Question"].ToString();   
    radioButton1.Text = table.Rows[0]["Answer 1"].ToString(); 
    radioButton2.Text = table.Rows[0]["Answer 2"].ToString();
    radioButton3.Text = table.Rows[0]["Answer 3"].ToString();
    radioButton4.Text = table.Rows[0]["Answer 4"].ToString();

    correctAnswer = table.Rows[0]["Correct Answer"].ToString(); ;
    questionNumber = 0;
  }
  conGet.Close();

}

private void btnGoToNextOne_Click(object sender, EventArgs e)
{
  String cnString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\Users\\Hannah\\Desktop\\QuizQuestions.accdb";

  OleDbConnection conGet = new OleDbConnection(cnString);
  OleDbCommand cmdGet = new OleDbCommand();

  {
    conGet.Open();

    cmdGet.CommandType = CommandType.Text;
    cmdGet.Connection = conGet;

    cmdGet.CommandText = "SELECT * FROM QuizQuestions ORDER BY rnd()";

    OleDbDataReader reader = cmdGet.ExecuteReader();
    reader.Read();

    if (radioButton1.Checked)
    {
      chosenAnswer = reader["Answer 1"].ToString();
    }
    else if (radioButton2.Checked)
    {
      chosenAnswer = reader["Answer 2"].ToString();
    }
    else if (radioButton3.Checked)
    {
      chosenAnswer = reader["Answer 3"].ToString();
    }
    else if (radioButton4.Checked)
    {
      chosenAnswer = reader["Answer 4"].ToString();
    }

    if (chosenAnswer == reader["Correct Answer"].ToString())
    {

        labelQuestion.Text = table.Rows[questionNumber]["Question"].ToString();
        //and show possible answers:
        radioButton1.Text = table.Rows[questionNumber]["Answer 1"].ToString();
        radioButton2.Text = table.Rows[questionNumber]["Answer 2"].ToString();
        radioButton3.Text = table.Rows[questionNumber]["Answer 3"].ToString();
        radioButton4.Text = table.Rows[questionNumber]["Answer 4"].ToString();
        correctAnswer = table.Rows[questionNumber]["Correct Answer"].ToString();
        questionNumber++;

    }
    else
    {
      MessageBox.Show("That is not the correct answer");
    }
  }
}

}
}

I know I need to put in “SELECT count(*) from QuizQuestions” but I’m not sure how I can determine the ‘position’ in the set of questions so that I don’t get this error:

IndexOutOfRangeException was unhandled
There is no row at position 5

Answer 1

It’s the “table.Rows[questionNumber]” that is killing you, you need to do a

table.Rows.Count check in that area. Something like

if (questionNumber < table.Rows.Count )