protected void btnExpense_Click(object sender, EventArgs e)
        {
            //Retrive Session variable to get UserID
            Int32 UserName = (Int32)(Session["UserName"]);
            try
            {

                using (ExpMgmtEntities db = new ExpMgmtEntities())
                {
                    //use the Expense model to save the new record
                    Expense ex = new Expense();
                    Account ac = new Account();
                    User us = new User();

                    us = (from objU in db.Users
                          where objU.UserID == UserName
                          select objU).FirstOrDefault();

                    ex.ExpType = ddlExpense.SelectedValue;
                    ex.ExpAmount = Convert.ToDouble(txtAmount.Text);
                    ex.UserID = UserName;
                    ex.Date = Convert.ToDateTime(DateTime.Today);
                    ex.AccountType = ddlAccountType.SelectedValue;

                    //Reduce expense amount from equivalent User account
                    if (ddlAccountType.SelectedValue == "Credit")
                    {
                        ac = (from objA in db.Accounts
                              where objA.UserID == us.UserID
                              select objA).FirstOrDefault();

                        ac.CreditBalance = ac.CreditBalance - Convert.ToDouble(txtAmount.Text);
                    }
                    else
                    {
                        ac = (from objA in db.Accounts
                              where objA.UserID == us.UserID
                              select objA).FirstOrDefault();

                        ac.DebitBalance = ac.DebitBalance - Convert.ToDouble(txtAmount.Text);
                    }
                    //run the update or insert
                    db.Expenses.Add(ex);
                    db.SaveChanges();
                    //redirect to the updated students page
                    Response.Redirect("/user/expense.aspx");
                }
            }
            catch
            {
                Response.Redirect("/errors.aspx");
            }
        }
        private void getExps(string startdate, string enddate, string acctype)
        {
            try
            {

                Int32 Uid = (Int32)(Session["UserName"]);
                using (ExpMgmtEntities db = new ExpMgmtEntities())
                {
                    Expense ex = new Expense();

                    if ((startdate != "") && (enddate != "") && (acctype != ""))
                    {
                        DateTime sd = Convert.ToDateTime(startdate);
                        DateTime ed = Convert.ToDateTime(enddate);
                        string at = ddlAccountType.SelectedValue;
                        var Exp = from e in db.Expenses
                                  where e.UserID == Uid && e.Date >= sd && e.Date <= ed && e.AccountType == at
                                  select new { e.ExpID, e.ExpType, e.Date, e.ExpAmount, e.AccountType };
                        if (Exp != null)
                        {
                            grdExpense.DataSource = Exp.ToList();
                            grdExpense.DataBind();
                        }
                        else
                        {
                            Response.Redirect("/user/expense.aspx");
                        }
                    }
                    else
                    {
                        var Exp = from e in db.Expenses
                                  where e.UserID == Uid
                                  select new { e.ExpID, e.ExpType, e.Date, e.ExpAmount, e.AccountType };
                        if (Exp != null)
                        {
                            grdExpense.DataSource = Exp.ToList();
                            grdExpense.DataBind();
                        }
                        else
                        {
                            Response.Redirect("/user/expense.aspx");
                        }
                    }
                }
            }
            catch
            {
                Response.Redirect("/errors.aspx");
            }
        }