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Online Exam in C# ASP NET

, 13 Sep 2010 CPOL
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Online Examination Project with CountDown Timer

Introduction

Most of us have come across Examination / Quiz projects. The important aspects of those projects is to have a timer that runs through the entire duration of the exam, having the timer running without reset by postbacks is the main concern of this article.

Background

The idea is to keep the value of the timer in view state and to supply the same on postback so that the timer will keep running from its previous value.

Using the Script

Understanding the script used here is not a big deal I guess, and am leaving it with a little explanation, go through the attachment for better understanding,

Timer is initiated in the page PreRender event, supplying the StartValue, Timerinterval and the clientId of the output element.

When the timer is started for the first timer, it is supplied with the duration of the examination say it is 30 min, and assume that the candidate spent 2 mins on a question and the postback occurs on 28 min, this value is kept in the view state and the same is used to start the timer again on the page PreRender event:

function myTimer(startVal,interval,outputId, dataField)
{
this.value = startVal;
this.OutputCntrl = document.getElementById(outputId);
this.currentTimeOut = null;
this.interval = interval;

myTimer.prototype.Seconds = function(value){
var hoursMillSecs = (this.Hours(value)*3600000)
var minutesMillSecs = (this.Minutes(value)*60000)
var total = (hoursMillSecs + minutesMillSecs)
var ans = Math.floor(((this.value - total)%60000)/1000);

this.OutputCntrl.innerHTML = this.Hours(current) + ':' + this.Minutes(current) 
+ ':' +  this.Seconds(current);
}

Keeping the Value in ViewState

You have to register the scrip with RegisterStartupScript in the codebehind file that supplies the view state value to the script and keeps the timer running.

Timer is initiated in PreRender event and the start value of the timer is requested from the view state and supplied to the timer, and this value changes on each postback as the exam is on progress.

void Page_PreRender(object sender, EventArgs e)
{ 
      StringBuilder bldr = new StringBuilder();
      bldr.AppendFormat("var Timer = new myTimer({0},{1},'{2}','timerData');",
          this.timerStartValue, this.TimerInterval, this.lblTimerCount.ClientID);
        
      bldr.Append("Timer.go()");

      ClientScript.RegisterStartupScript(this.GetType(), "TimerScript",
                                    bldr.ToString(), true);

      ClientScript.RegisterHiddenField("timerData", timerStartValue.ToString());
}

// Gets or Sets the Timer Value to the ViewState
private Int32 TimerInterval
{
  get
  {
    object o = ViewState["timerInterval"];
    if (o != null) { return Int32.Parse(o.ToString()); }
    return 50;
  }
  set
  {
    ViewState["timerInterval"] = value; 
  }
}  

Hope this will be a help to start your project. The attachment is prepared as a template that you can use for your project and can extend to meet your requirements.

History

  • 13th September, 2010: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

VallarasuS
Software Developer
India India
I code, learn, listen, and some day in a near future be a proud farmer.
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Comments and Discussions

 
GeneralRe: database for quiz Pinmembertesstaco1-May-12 9:07 
QuestionTimer Pinmembersammaed29-Jan-12 20:10 
AnswerRe: Timer PinmemberVallarasuS30-Jan-12 5:03 
GeneralRe: Timer Pinmembersammaed30-Jan-12 7:32 
GeneralRe: Timer PinmemberVallarasuS30-Jan-12 8:05 
GeneralRe: Timer PinmemberMember 994730327-Mar-13 18:32 
QuestionDATA base PinmemberRajeshkrathor28-Dec-11 20:40 
AnswerRe: DATA base PinmemberVallarasuS29-Dec-11 16:15 
Actual implementation should go inside ConnectToDb.cs -> GetDataSet() method which will populate the questions from db, for demonstration I've added a dummy dataset within the method, so source with this article does not requires a db to execute.
Regards Vallarasu S | BreakingDotNet.blogspot.com

GeneralMy vote of 4 Pinmemberkitupadma30-Oct-11 20:43 
GeneralRe: My vote of 4 Pinmembervallarasus17-Nov-11 5:18 
QuestionExam Questions in a SQLDB Pinmemberjpiscitelli20-Oct-11 5:09 
AnswerRe: Exam Questions in a SQLDB Pinmembervallarasus20-Oct-11 7:53 
GeneralRe: Exam Questions in a SQLDB Pinmemberjpiscitelli21-Oct-11 3:38 
GeneralRe: Exam Questions in a SQLDB PinmemberMember 963246926-Nov-12 12:19 
GeneralMy vote of 2 Pinmembersurendramarri12-Jan-11 1:57 
GeneralMy vote of 4 PinmemberHardikKSavaliya6-Dec-10 4:42 
GeneralMy vote of 3 Pinmembersaxenaabhi613-Sep-10 20:21 
GeneralRe: My vote of 3 Pinmembervallarasus1-Jun-11 9:55 
GeneralMy vote of 1 Pinmemberj03x213-Sep-10 8:31 
GeneralMy vote of 2 PinmentorSandeep Mewara28-Aug-10 6:41 

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