multiuser log in at same time - sql

Question

I have created an online examination system. It is working fine with only a single user at a time. However, a problem occurs when more than one user logs in.
There are 20 questions in each test. If only a single user is doing the test it works fine. The user can do all the 20 questions. Now another user logs in at the same time. That user is not getting all the 20 questions. Say User1 has completed 12 question. User2 will get only 8 question.
Suppose there there are User1,User2,User3 logged in at the same time. User1 did 8 questions, User2 did 6 questions and User3 also 8 questions. They would all arrive at the result Page without completing their 20 questions. That means if there are 20 users they will get only 1 question instead of 20. Can anyone help?
try
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["hasexaminationConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand();
SqlDataReader dr;
cmd.Connection = con;
cmd.CommandText = "select * from tblregister where Name=#Name and EMail=#EMail";
cmd.Parameters.Add("#Name", SqlDbType.VarChar).Value = TxtStName.Text;
cmd.Parameters.Add("#EMail", SqlDbType.VarChar).Value = TxtStudentID.Text;
//cmd.Parameters.Add("#Flag", SqlDbType.Int).Value = Convert.ToInt32(HiddenField1.Value);
con.Open();
dr = cmd.ExecuteReader();
if (dr.Read())
{
FormsAuthentication.RedirectFromLoginPage(TxtStName.Text, false);
Session["Name"] = TxtStName.Text;
Session["EMail"] = TxtStudentID.Text;
Response.Redirect("TestHome.aspx");
}
else
{
Label1.Visible = true;
Label1.Text = "UserName or Password is Required/Incorrect.";
}
}
catch
{ }
}
next page:
protected void Page_Load(object sender, EventArgs e)
{
mob = HttpContext.Current.Session["Name"].ToString();
number = HttpContext.Current.Session["EMail"].ToString();
//Response.Cache.SetCacheability(HttpCacheability.NoCache);
if (Session["mob"] == null & Session["number"] == null)
//Response.Redirect("Home.aspx");
if (!IsPostBack)
{
DataSet TestList = getTestList("GetTestList");
DataList1.DataSource = TestList;
DataList1.DataBind();
}
}
public DataSet getTestList(string procedurename)
{
using (DataSet QuestionSet = new DataSet())
{
using (DataTable QTable = new DataTable())
{
QTable.Columns.Add("TESTNAME");
QTable.Columns.Add("TESTNUMBER");
DataTable dt;
cmd.Connection = con;
cmd.CommandText = "select * from testnumber";
using (Da = new SqlDataAdapter(cmd))
{
con.Open();
dt = new DataTable();
Da.Fill(dt);
if (dt.Rows.Count > 0)
{
DataRow dr;
for (int i = 0; i < dt.Rows.Count; i++)
{
dr = QTable.NewRow();
dr[0] = dt.Rows[i]["testname"].ToString();
dr[1] = dt.Rows[i]["testnumber"].ToString();
QTable.Rows.Add(dr);
}
}
}
QuestionSet.Tables.Add(QTable);
return QuestionSet;
}
}
}
protected void LinkButton_Click(object sender, CommandEventArgs e)
{
string name = e.CommandArgument.ToString();
Response.Redirect("TakeTest1.aspx?testno=" + e.CommandArgument.ToString());
}
next:
protected void Page_Load(object sender, EventArgs e)
{
//UserName = Session["UserName"].ToString();
//Password = Session["Password"].ToString();
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["hasexaminationConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand();
SqlDataReader dr;
cmd.Connection = con;
cmd.CommandText = "select username,password,flag from tblcollegeuser where username='" + UserName + "'and password='" + Password + "'";
con.Open();
dr = cmd.ExecuteReader();
if (dr.Read())
{
HiddenField1.Value = dr["Flag"].ToString();
if (HiddenField1.Value.ToString() == "0")
{
//Response.Write("<script>alert('Your Session Timer has Expired! We are Sorry!')</script>");
Response.Redirect("Result.aspx");
}
}
if (HttpContext.Current.Session["Name"] == null && HttpContext.Current.Session["EMail"] == null)
{
Response.Write("<script>alert('Your Session Timer has Expired! We are Sorry!')</script>");
Response.Redirect("default.aspx");
}
if (!IsPostBack)
{
this.timerStartValue = long.Parse(ConfigurationManager.AppSettings["Delay"].ToString());
this.TimerInterval = 500;
tno = Request.QueryString["testno"].ToString();
//string query = "select * from questions where tnumber='" + tno + "'";
Questions = GetDataSet(tno);
totalQs = GetCount(tno);
LoadQuestion();
DataSet questions = new DataSet("Questions");
questions.Tables.Add();
}
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
string strDisAbleBackButton;
strDisAbleBackButton = "";
ClientScript.RegisterClientScriptBlock(this.Page.GetType(), "clientScript", strDisAbleBackButton);
}
public DataSet GetDataSet(string query)
{
using (DataSet QuestionSet = new DataSet())
{
using (DataTable QTable = new DataTable())
{
QTable.Columns.Add("ROW_NUMBER");
QTable.Columns.Add("QuestionNo");
QTable.Columns.Add("Tname");
QTable.Columns.Add("Tnumber");
QTable.Columns.Add("question");
QTable.Columns.Add("ans1");
QTable.Columns.Add("ans2");
QTable.Columns.Add("ans3");
QTable.Columns.Add("ans4");
DataTable dt;
using (cmd.Connection = con)
{
//cmd.CommandText = " SELECT * FROM test ORDER BY CHECKSUM(NEWID()) where tnumber='" + query + "'";
cmd.CommandText = " SELECT * FROM test WHERE tnumber='" + query + "' ORDER BY CHECKSUM(NEWID()) ";
//cmd.Parameters.AddWithValue("#cse", query);
Da = new SqlDataAdapter(cmd);
con.Open();
dt = new DataTable();
Da.Fill(dt);
if (dt.Rows.Count > 0)
{
DataRow dr;
for (int i = 0; i < dt.Rows.Count; i++)
{
dr = QTable.NewRow();
dr[0] = dt.Rows[i]["id"].ToString();
dr[1] = "Qno" + dt.Rows[i]["Qno"].ToString();
dr[2] = dt.Rows[i]["tname"].ToString();
dr[3] = dt.Rows[i]["tnumber"].ToString();
dr[4] = dt.Rows[i]["quation"].ToString();
dr[5] = dt.Rows[i]["ans1"].ToString();
dr[6] = dt.Rows[i]["ans2"].ToString();
dr[7] = dt.Rows[i]["ans3"].ToString();
dr[8] = dt.Rows[i]["ans4"].ToString();
QTable.Rows.Add(dr);
}
}
}
QuestionSet.Tables.Add(QTable);
return QuestionSet;
}
}
}
public Int32 GetCount(string tno)
{
return 10;
}
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());
}
void Page_PreInit(object sender, EventArgs e)
{
string timerVal = Request.Form["timerData"];
if (timerVal != null || timerVal == "")
{
timerVal = timerVal.Replace(",", String.Empty);
timerStartValue = long.Parse(timerVal);
}
}
private Int32 TimerInterval
{
get
{
object o = ViewState["timerInterval"];
if (o != null) { return Int32.Parse(o.ToString()); }
return 50;
}
set { ViewState["timerInterval"] = value; }
}
void RedirectToResults()
{
Response.Redirect("Results.aspx");
}
protected void LoadQuestion()
{
if (Questions.Tables[0].Rows.Count > 0)
{
//Load Question;
DataRow DR = Questions.Tables[0].Rows[0];
//Question.Text = DR[0].ToString() + " of " + 20;
//Question.Text = (i + 1).ToString() + " of " + 20;
sno = DR[1].ToString();
TestName.Text = DR[2].ToString();
TestNo.Text = DR[3].ToString();
Questionlbl.Text = DR[4].ToString();
rbtnAns.Items.Clear();
rbtnAns.Items.Add(DR[5].ToString());
rbtnAns.Items.Add(DR[6].ToString());
rbtnAns.Items.Add(DR[7].ToString());
rbtnAns.Items.Add(DR[8].ToString());
Questions.Tables[0].Rows.Remove(DR);
if (Questionlbl.Text.Equals(totalQs.ToString()))
{
IsLastQs = true;
}
}
else
{
//End Of File;
//Response.Write("<script>alert('Thanks For Your Presence! You Can Leave Now.')</script>");
//Session.Abandon();
Session["raj"] = Questions;
RedirectToResults();
}
}
protected void Button1_Click(object sender, EventArgs e)
{
try
{
//Write your code here to save the question
//Displays the Next Question
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["hasexaminationConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand("insert into testdisplay Values ('" + sno + "','" + Session["Name"] + "','" + Session["EMail"] + "','" + Questionlbl.Text + "','" + rbtnAns.SelectedItem.Text + "')", con);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
LoadQuestion();
}
catch (Exception ex)
{
Response.Write("<script>alert(''" + ex.Message + "'')</script>");
}
}
protected void Button2_Click(object sender, EventArgs e)
{
//When Skip Button is pressed it loads the next question
LoadQuestion();
}
and result page:
protected void Page_Load(object sender, EventArgs e)
{
l = Session["Name"].ToString();
m = Session["EMail"].ToString();
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["hasexaminationConnectionString"].ConnectionString);
SqlCommand cmd = new SqlCommand("select tnumber,quation,ans1,ans2,ans3,ans4,ans from test left join testdisplay on (test.ans= testdisplay.answ and test.quation= testdisplay.quations) where UserName='" + Session["Name"] + "' and Password='" + Session["EMail"] + "'", con);
con.Open();
SqlDataAdapter adp = new SqlDataAdapter(cmd);
adp.Fill(dt);
con.Close();
{
int to = 20;
GridView1.DataSource = dt;
GridView1.DataBind();
int marks = GridView1.Rows.Count;
Label1.Text = Convert.ToInt32(GridView1.Rows.Count).ToString();
decimal total = Convert.ToDecimal((double)marks / (double)20) * 100;
lbltotal.Text = total.ToString();
}
}
public void bind()
{
// Write your code to get the summary of the result and display it
}
protected void Button1_Click(object sender, EventArgs e)
{
//Response.Redirect("Home.aspx");
string uniqueCode = string.Empty;
//SqlDataReader dr;
try
{
DataSet ds = new DataSet();
using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["hasexaminationConnectionString"].ConnectionString))
{
con.Open();
SqlCommand cmd = new SqlCommand("SELECT Name,EMail FROM tblregister Where EMail= '" + txtEmail.Text.Trim() + "'", con);
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds);
////}
if (Page.IsValid)
{
//GridView1.RenderControl(hw);
const string SERVER = "relay-hosting.secureserver.net";
MailMessage oMail = new MailMessage();
oMail.From = new MailAddress("contact#dssgroups.com");
oMail.To.Add(new MailAddress(txtEmail.Text.Trim()));
oMail.Subject = "Your Test Details";
oMail.IsBodyHtml = true; // enumeration
oMail.Priority = MailPriority.High; // enumeration
oMail.Body = "Hi, <br/><b>Please check your Test Details:</b><br/><br/>Your Marks Percentage: " + lbltotal.Text+" % "+"<br/>For any query contact "+" http://dssgroups.com";
SmtpClient sC = new SmtpClient(SERVER);
sC.EnableSsl = false;
ContentType contentType = new ContentType();
contentType.MediaType = MediaTypeNames.Application.Octet;
contentType.Name = "xml.xml";
sC.Send(oMail);
oMail = null; // free up resources
lblMessage.ForeColor = System.Drawing.Color.DarkKhaki;
lblMessage.Text = "EMail Sent";
ScriptManager.RegisterStartupScript(this, GetType(), "showalert", "alert('EMail Sent');", true);
}
else
{
lblMessage.Text = "The Email you entered not exists.";
}
}
//}
}
catch (Exception ex)
{
Console.WriteLine("{0} Exception caught.", ex);
}
}
protected void Button2_Click(object sender, EventArgs e)
{
Session.Clear();
Session.Abandon();
Response.Redirect("default.aspx");
}