asp.net site stops normal working after executing the page - asp.net

Question

I am working on asp.net project. I add one new page here and on that page i call multiple stored procedure. After executing this page for some time my site stops working and continue refreshing on browser without giving any error. After restarting the server it starts work again.
private void GetBiometrixData()
{
try
{
string data = string.Empty;
var length = ddlsession.Items.Count;
for (int i = 0; i < length; i++)
{
if (ddlsession.Items[i].Selected == true)
{
if (ddlsession.Items[i].Text != "--Select--")
{
data += ddlsession.Items[i].Text + ",";
}
}
}
data = data.Length > 0 ? data.Substring(0, data.Length - 1) : "";
data = data.Trim();
String strConnString = ConfigurationManager.ConnectionStrings["ak"].ConnectionString;
DateTime? FromDate = null;
DateTime? ToDate = null;
string session = "";
string TrainingType = "";
string EmployeeName = "";
string Course = "";
string Batch = "";
CultureInfo provider = CultureInfo.InvariantCulture;
string format = "MM/dd/yyyy";
if (string.IsNullOrEmpty(txtFromDate.Text.ToString()))
{
string TodayDate = DateTime.Now.ToString("MM/dd/yyyy");
FromDate = DateTime.ParseExact(TodayDate.ToString().Trim(), format, provider);
}
else
FromDate = DateTime.ParseExact(txtFromDate.Text.ToString().Trim(), format, provider);
if (string.IsNullOrEmpty(txtToDate.Text.ToString()))
ToDate = null;
else
ToDate = DateTime.ParseExact(txtToDate.Text.ToString().Trim(), format, provider);
if (ddlsession.SelectedItem.Text.ToString() == "--Select--")
session = null;
else
session = ddlsession.SelectedItem.Text.ToString();
if ((ddltrainingtype.SelectedItem.Text.ToString() == "--Select Training Type--"))
TrainingType = null;
else
TrainingType = ddltrainingtype.SelectedItem.Text.ToString();
if ((ddlCourse.SelectedItem.Text.ToString() == "--Select Course--"))
Course = null;
else
Course = ddlCourse.SelectedValue.ToString();
if ((ddlbatch.SelectedItem.Text.ToString() == "--Select Batch--"))
Batch = null;
else
Batch = ddlbatch.SelectedValue.ToString();
if (!string.IsNullOrEmpty(txtEmployeeName.Text.ToString()))
EmployeeName = txtEmployeeName.Text.ToString();
string strStatus = "";
if (Session["strStatus"] != null)
{
strStatus = Convert.ToString(Session["strStatus"]);
}
DataSet dsCount = new DataSet();
using (SqlConnection con = new SqlConnection(strConnString))
{
using (SqlCommand cmd = new SqlCommand())
{
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = con;
cmd.CommandTimeout = 0;
cmd.CommandText = "SP_GetBiometricAttendanceReport2";
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime).Value = FromDate;
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime).Value = ToDate;
cmd.Parameters.Add("#Session", SqlDbType.VarChar).Value = data;
cmd.Parameters.Add("#TrainingType", SqlDbType.VarChar).Value = TrainingType;
cmd.Parameters.Add("#Course", SqlDbType.VarChar).Value = Course;
cmd.Parameters.Add("#Batch", SqlDbType.VarChar).Value = Batch;
cmd.Parameters.Add("#EmployeeName", SqlDbType.VarChar).Value = EmployeeName;
cmd.Parameters.Add("#TotalStudents", SqlDbType.BigInt);
cmd.Parameters["#TotalStudents"].Direction = ParameterDirection.Output;
cmd.Parameters.Add("#TotalPresentStudents", SqlDbType.BigInt);
cmd.Parameters["#TotalPresentStudents"].Direction = ParameterDirection.Output;
cmd.Parameters.Add("#TotalAbsentStudents", SqlDbType.BigInt);
cmd.Parameters["#TotalAbsentStudents"].Direction = ParameterDirection.Output;
sda.SelectCommand = cmd;
sda.Fill(dsCount);
tblSummary.Visible = true;
lblTotalDrive.Text = cmd.Parameters["#TotalStudents"].Value.ToString();
lblTotalStudentAttended.Text = cmd.Parameters["#TotalPresentStudents"].Value.ToString();
lblTotalStudentAbsent.Text = cmd.Parameters["#TotalAbsentStudents"].Value.ToString();
}
}
}
DataSet ds = new DataSet();
using (SqlConnection con = new SqlConnection(strConnString))
{
using (SqlCommand cmd = new SqlCommand())
{
using (SqlDataAdapter sda = new SqlDataAdapter())
{
if (!string.IsNullOrEmpty(Convert.ToString(FromDate)) && !string.IsNullOrEmpty(Convert.ToString(ToDate)))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = con;
cmd.CommandTimeout = 0;
cmd.CommandText = "SP_GetBiometricAttendanceReportCount";
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime).Value = FromDate;
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime).Value = ToDate;
cmd.Parameters.Add("#Session", SqlDbType.VarChar).Value = data;
cmd.Parameters.Add("#TrainingType", SqlDbType.VarChar).Value = TrainingType;
cmd.Parameters.Add("#Course", SqlDbType.VarChar).Value = Course;
cmd.Parameters.Add("#Batch", SqlDbType.VarChar).Value = Batch;
cmd.Parameters.Add("#EmployeeName", SqlDbType.VarChar).Value = EmployeeName;
sda.SelectCommand = cmd;
sda.Fill(ds);
tblSummary.Visible = false;
GridView2.Visible = false;
RadGrid1.Visible = false;
GridView1.Visible = true;
GridView1.DataSource = ds.Tables[0];
GridView1.DataBind();
//RadGrid1.DataSource = ds.Tables[0];
//RadGrid1.Rebind();
}
else
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = con;
cmd.CommandTimeout = 0;
cmd.CommandText = "SP_GetBiometricAttendanceReport";
cmd.Parameters.Add("#FromDate", System.Data.SqlDbType.DateTime).Value = FromDate;
cmd.Parameters.Add("#ToDate", System.Data.SqlDbType.DateTime).Value = ToDate;
cmd.Parameters.Add("#Session", SqlDbType.VarChar).Value = session;
cmd.Parameters.Add("#TrainingType", SqlDbType.VarChar).Value = TrainingType;
cmd.Parameters.Add("#Course", SqlDbType.VarChar).Value = Course;
cmd.Parameters.Add("#EmployeeName", SqlDbType.VarChar).Value = EmployeeName;
cmd.Parameters.Add("#Status", SqlDbType.VarChar).Value = strStatus;
cmd.Parameters.Add("#Batch", SqlDbType.VarChar).Value = Batch;
sda.SelectCommand = cmd;
sda.Fill(ds);
GridView2.DataSource = ds.Tables[0];
GridView2.DataBind();
RadGrid1.DataSource = ds.Tables[0];
RadGrid1.Rebind();
if (strStatus == "")
lblResultStatus.Text = "<strong>Result of Total Students >></strong>";
else
lblResultStatus.Text = "<strong>Result of Total " + strStatus + " Students >></strong>";
}
}
}
}
}
catch (Exception ex)
{
Response.Write(ex.Message);
//throw ex;
}
finally
{
con.Dispose();
con.Close();
}
}
Please help me to resolve this why site stops normal working and need to restart the server again and again.
Thanks...