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Posted 13 Sep 2010

Online Exam in C# ASP NET

, 13 Sep 2010 CPOL
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Online Examination Project with CountDown Timer


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.


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);

      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
    object o = ViewState["timerInterval"];
    if (o != null) { return Int32.Parse(o.ToString()); }
    return 50;
    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.


  • 13th September, 2010: Initial post


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


About the Author

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

QuestionMessage Automatically Removed Pin
23-May-12 19:11
memberMember 869876723-May-12 19:11 
Questiondatabase for quiz Pin
mbjino15-Apr-12 21:27
membermbjino15-Apr-12 21:27 
AnswerRe: database for quiz Pin
mbjino15-Apr-12 21:29
membermbjino15-Apr-12 21:29 
GeneralRe: database for quiz Pin
VallarasuS15-Apr-12 23:47
memberVallarasuS15-Apr-12 23:47 
GeneralRe: database for quiz Pin
mbjino16-Apr-12 4:01
membermbjino16-Apr-12 4:01 
GeneralRe: database for quiz Pin
tesstaco1-May-12 9:07
membertesstaco1-May-12 9:07 
QuestionTimer Pin
sammaed29-Jan-12 20:10
membersammaed29-Jan-12 20:10 
AnswerRe: Timer Pin
VallarasuS30-Jan-12 5:03
memberVallarasuS30-Jan-12 5:03 
sammaed wrote:
1. We are not able to find the suitable timer program , Time has to be displayed at every second on the screen.

Did you try adopting this script in your app? port the script and the code behind snippets!

sammaed wrote:
2. we have provided the button, we need to change the color of the buttons when the question has been answered.

If I understood your requirement correctly it must be easy to change the background in checkbox's checked event! can you brief if yours is different situation?
Regards Vallarasu S |

GeneralRe: Timer Pin
sammaed30-Jan-12 7:32
membersammaed30-Jan-12 7:32 
GeneralRe: Timer Pin
VallarasuS30-Jan-12 8:05
memberVallarasuS30-Jan-12 8:05 
GeneralRe: Timer Pin
Member 994730327-Mar-13 18:32
memberMember 994730327-Mar-13 18:32 
QuestionDATA base Pin
Rajeshkrathor28-Dec-11 20:40
memberRajeshkrathor28-Dec-11 20:40 
AnswerRe: DATA base Pin
VallarasuS29-Dec-11 16:15
memberVallarasuS29-Dec-11 16:15 
GeneralMy vote of 4 Pin
kitupadma30-Oct-11 20:43
memberkitupadma30-Oct-11 20:43 
GeneralRe: My vote of 4 Pin
vallarasus17-Nov-11 5:18
membervallarasus17-Nov-11 5:18 
QuestionExam Questions in a SQLDB Pin
jpiscitelli20-Oct-11 5:09
memberjpiscitelli20-Oct-11 5:09 
AnswerRe: Exam Questions in a SQLDB Pin
vallarasus20-Oct-11 7:53
membervallarasus20-Oct-11 7:53 
GeneralRe: Exam Questions in a SQLDB Pin
jpiscitelli21-Oct-11 3:38
memberjpiscitelli21-Oct-11 3:38 
GeneralRe: Exam Questions in a SQLDB Pin
Member 963246926-Nov-12 12:19
memberMember 963246926-Nov-12 12:19 
GeneralMy vote of 2 Pin
surendramarri12-Jan-11 1:57
membersurendramarri12-Jan-11 1:57 
GeneralMy vote of 4 Pin
HardikKSavaliya6-Dec-10 4:42
memberHardikKSavaliya6-Dec-10 4:42 
GeneralMy vote of 3 Pin
saxenaabhi613-Sep-10 20:21
membersaxenaabhi613-Sep-10 20:21 
GeneralRe: My vote of 3 Pin
vallarasus1-Jun-11 9:55
membervallarasus1-Jun-11 9:55 
GeneralMy vote of 1 Pin
j03x213-Sep-10 8:31
memberj03x213-Sep-10 8:31 
GeneralMy vote of 2 Pin
Sandeep Mewara28-Aug-10 6:41
mentorSandeep Mewara28-Aug-10 6:41 

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