Creating Dynamic Web Quizzes using C# and ASP.NET

Figure 1: Snapshot of the generated Web Quiz.

Just when you thought you'd never see another test again, your back in school, sharpening that #2 pencil and blowing away erasure particles. Well maybe not anymore thanks to the power of C# and .NET!  You may still be taking tests, but you probably won't have to go out and buy a sharpener. This article describes how to create a web quiz from the information in a database. For the purposes of this article, I chose to use MS Access, but the code can be altered easy enough to use SqlServer, MySql, Oracle, or whatever your favorite provider happens to be. Below is the Database Schema for our Quiz:

Figure 2: This Access Database was reverse engineered using WithClass 2000

The structure of the Database is fairly simple. The questions are stored in the Questions Table along with the answers. The Choices are stored in the Choices table and are pointed to by the QuestionID key. The StatsTable holds the title and NumberOfQuestions. Finally, the Testers table holds the information for the people taking the test. (This table is not utilized in this example, but will be in part II of this article.)   

The web page for the quiz is constructed on the fly using Microsoft WebForms, Tables, TableRows, and TableCells. Below is the code that reads the MSAccess data using ADO.NET and creates the table. Note that all of this is done in the PageLoad Event:

private void Page_Load(object sender, System.EventArgs e)

{ 

    if (!IsPostBack)

    {

        //  This is the Initial Page Load.  Draw the Quiz

        ReadQuizTitle();

        ReadQuestionsIntoTable();

        AddSubmitButton();

    }

    else

    {

        //  The User has pressed the score button, calculate and publish the results

        HttpRequest r;

        r = this.Request;

        bool AreAllAnswered = CalculateScore(r);

        HttpResponse rs;

        rs = this.Response;

        if (AreAllAnswered == false)

        {

            rs.Write("You missed a few questions. Go back in your browser and answer them<P>");

            return;

        }

        //  Write the score

        rs.Write("Your score is " + NumberCorrect.ToString() + " out of " + NumberOfQuestions.ToString() +

        "<P>");

        //  Print out the corrected answers

        for (int num = 0; num < NumberOfQuestions; num++)

        {

            if (WrongArray[num].Length > 0)

                rs.Write(WrongArray[num]);

        }

        //  Rank the User

        rs.Write(GetRanking());

    }

} 

The first half of the if statement is handled when the page first loads. This part is responsible for drawing the quiz. The second half of the if statement is executed after the user presses the Score Button. This part of the if statement will score the test and output a page giving the score, the missed questions, and a ranking.

Unfortunately, you can't tell much from the code above. So let's delve into what's happening in the ReadQuestionsIntoTable Routine:

private void ReadQuestionsIntoTable()

{

    // Fill the questions and choices tables in memory

    DataSet ds1 = new DataSet("questionsds");

    oleDbDataAdapter1.Fill(ds1, "Questions");

    oleDbDataAdapter2.Fill(ds1, "Choices");

    DataTable QuestionsTable = ds1.Tables["Questions"];

    DataTable ChoicesTable = ds1.Tables["Choices"];

    // create a data relation between the Questions and Choices Tables

    // so we can cycle through the choices for each question

    DataRelation QALink = new DataRelation("QuestionLink", QuestionsTable.Columns["QuestionID"],

    ChoicesTable.Columns["QuestionID"]);

    QuestionsTable.ChildRelations.Add(QALink);

    NumberOfQuestions = 0;

    // go through every row in the questions table

    // and place each question in the Table Web Control

    foreach (DataRow dr in QuestionsTable.Rows)

    {

        // create a row for the question and read it from the database

        TableRow tr = new TableRow();

        Table1.Rows.Add(tr);

        TableCell aCell = new TableCell();

        // get the text for the question and stick it in the cell

        aCell.Text = dr["QuestionText"].ToString();

        tr.Cells.Add(aCell);

        AnswerArray[NumberOfQuestions] = dr["Answer"].ToString();

        // create a row for the choices and read from the database

        int count = 0;

        // go through the child rows of the question table

        // established by the DataRelation QALink and

        // fill the choices for the table

        foreach (DataRow choiceRow in dr.GetChildRows(QALink))

        {

            TableRow tr2 = new TableRow();

            Table1.Rows.Add(tr2);

            // create a cell for the choice

            TableCell aCell3 = new TableCell();

            aCell3.Width = 1000;

            // align the choices on the left

            aCell3.HorizontalAlign = HorizontalAlign.Left;

            tr2.Cells.Add(aCell3);

 

            // create a radio button in the cell

            RadioButton rb = new RadioButton();

            // assign the radio button to Group + QuestionID

            rb.GroupName = "Group" + choiceRow["QuestionID"].ToString();

 

            // Assign the choice to the radio button

            rb.Text = choiceRow["ChoiceLetter"].ToString() + ". " + choiceRow["ChoiceText"].ToString();

            // Assign the radio button id corresponding to the choice and question # 

            rb.ID = "Radio" + NumberOfQuestions.ToString() + Convert.ToChar(count + 65);

            rb.Visible = true;

            // add the radio button to the cell

            aCell3.Controls.Add(rb);

            count++;

        }

        // add a table row between each question

        // as a spacer

        TableRow spacer = new TableRow();

        spacer.Height = 30;

        TableCell spacerCell = new TableCell();

        spacerCell.Height = 30;

        spacer.Cells.Add(spacerCell);

        Table1.Rows.Add(spacer); // add a spacer

        //  Increment the # of Questions

        NumberOfQuestions++;

    }

} 

The code above uses ADO.NET to cycle through all the questions and choices and place them in the table on the WebForm. The program uses the Table, TableCell, TableRow WebControls to display the questions in a decent format. 

After the user fills in the quiz, It's time to score the test. The results are compared against the QuestionTable's answers and then computed and printed during the PostBack( after the Score button is pressed). The program takes advantage of the nice features of the HttpRequest object to extract the test results. The HttpRequest has a Form property that contains all the Key-Value pair information in a nice hash table. The program goes through each of the Keys in the Request and hashes out the results in each Radio Group. The Value passed by the Request contains the testtakers answers:

private bool CalculateScore(HttpRequest r)

{

    // initialize wrong answer array

    WrongArray.Initialize();

    // Load up statistic table to get Number of Questions

    DataSet ds = new DataSet("StatsDS");

    oleDbDataAdapter4.MissingSchemaAction = MissingSchemaAction.AddWithKey;

    this.oleDbDataAdapter4.Fill(ds, "StatsTable");

    DataTable StatsTable = ds.Tables["StatsTable"];

    NumberOfQuestions = (int)StatsTable.Rows[0]["NumberOfQuestions"];

    // Load up Questions Table to Get Answers to

    // compare to testtaker

    oleDbDataAdapter1.MissingSchemaAction = MissingSchemaAction.AddWithKey;

    DataSet ds1 = new DataSet("questionsds");

    oleDbDataAdapter1.Fill(ds1, "Questions");

    DataTable QuestionTable = ds1.Tables["Questions"];

    // Load up choices table to print out correct choices

    DataSet ds2 = new DataSet("choicesDS");

    oleDbDataAdapter2.MissingSchemaAction = MissingSchemaAction.AddWithKey;

    oleDbDataAdapter2.Fill(ds2, "Choices");

    DataTable ChoicesTable = ds2.Tables["Choices"];

    // make sure all questions were answered by the tester

    int numAnswered = CalcQuestionsAnsweredCount(r);

    if (numAnswered != NumberOfQuestions)

    {

        return false;

    }

    NumberCorrect = 0;

    NumberWrong = 0;

    // initialize wrong answer array to empty string

    for (int j = 0; j < NumberOfQuestions; j++)

    {

        WrongArray[j] = "";

    }

    // cycle through all the keys in the returned Http Request Object

    for (int i = 0; i < r.Form.Keys.Count; i++)

    {

        string nextKey = r.Form.Keys[i];

        // see if the key contains a radio button Group

        if (nextKey.Substring(0, 5) == "Group")

        {

            // It contains a radiobutton, get the radiobutton ID from the hashed Value-Pair Collection

            string radioAnswer = r.Form.Get(nextKey);

            // extract the letter choice of the tester from the button ID

            string radioAnswerLetter = radioAnswer[radioAnswer.Length - 1].ToString();

            // extract the question number from the radio ID

            string radioQuestionNumber = radioAnswer.Substring(5);

            radioQuestionNumber = radioQuestionNumber.Substring(0, radioQuestionNumber.Length - 1);

            int questionNumber = Convert.ToInt32(radioQuestionNumber, 10) + 1;

            // now compare the testers answer to the answer in the database

            DataRow dr = QuestionTable.Rows.Find(questionNumber);

            if (radioAnswerLetter == dr["Answer"].ToString())

            {

                // tester got it right, increment the # correct

                NumberCorrect++;

                CorrectArray[questionNumber - 1] = true;

                WrongArray[questionNumber - 1] = "";

            }

            else

            {

                // tester got it wrong, increment the # incorrect

                CorrectArray[questionNumber - 1] = false;

                // look up the correct answer

                string correctAnswer = ChoicesTable.Rows.Find(dr["AnswerID"])["ChoiceText"].ToString();

                // put the correct answer in the Wrong Answer Array.

                WrongArray[questionNumber - 1] = "Question #" + questionNumber + " - <B>" + dr

                ["Answer"].ToString() + "</B>. " + correctAnswer + "<BR>\n";

                // increment the # of wrong answers

                NumberWrong++;

            }

        }

    }

    return true;

}

That's all there is to it!  In part 2 I plan on adding a web form that gets the testers anonymous ID so that the scores can be collected for each test taker and a test curve can be generated.