ChecckIn.txt

Imports System.Data.SqlClient

Public Class frmCheckin
Dim guestID, roomID, trans_ID As Integer

Private Sub frmCheckin_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
    Dim a As String = MsgBox("Cancel Transaction?", vbQuestion + vbYesNo, "Cancel")
    If a = vbNo Then
        e.Cancel = True
    Else
        clear_text()
    End If
End Sub
Private Sub frmCheckin_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    clear_text()
    Dim time As DateTime = DateTime.Now
    Dim format As String = "MM/d/yyyy"
    txtCheckInDate.Text = time.ToString(format)
    dtCheckOutDate.Text = Now.AddDays(1D)
    transID()
    pop_discount()
    display_checkin()
End Sub

Public Sub transID()
    con.Open()
    Dim dt As New DataTable("tblTransaction")
    Dim cmd As New SqlCommand("SELECT TOP 1 * FROM tblTransaction ORDER BY TransID DESC", con)
    Dim da As New SqlDataAdapter(cmd)
    da.Fill(dt)

    If dt.Rows.Count = 0 Then
        txtTransID.Text = "TransID - 0001"
    Else
        Dim value As Integer = Val(dt.Rows(0).Item("TransID"))
        value = value + 1
        txtTransID.Text = "TransID - " & value.ToString("0000")
        trans_ID = value
    End If
    da.Dispose()
    con.Close()
End Sub

Private Sub bttnCheckIn_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bttnCheckIn.Click
    Dim children As Integer = Val(txtChildren.Text)
    Dim adult As Integer = Val(txtAdults.Text)
    Dim advance As Integer = Val(txtAdvance.Text)
    Dim discount As Integer = Val(lblDiscountID.Text)
    Dim reserve As String = "0"
    Dim remarks As String = "Checkin"
    Dim stat As String = "Active"

    If lblGuestID.Text = "GuestID" Or lblGuestID.Text = Nothing Or txtRoomNumber.Text = Nothing Or Val(children + adult) = Nothing Or advance = Nothing Or discount = Nothing Then
        MsgBox("Please Fill All Fields", vbInformation, "Note")
    Else
        If Val(Val(txtSubTotal.Text) * 0.5) > Val(txtAdvance.Text) Then
            MsgBox("Ops")
            Exit Sub
        End If
        Dim a As String = MsgBox("Confirm Checkin Transaction?", vbQuestion + vbYesNo, "Check In")
        If a = vbYes Then
            con.Open()
            Dim checkin As New SqlCommand("INSERT INTO tblTransaction(GuestID,RoomNum,CheckInDate,CheckOutDate,NoOfChild,NoOfAdult,AdvancePayment,DiscountID,Remarks,Status) values ('" &
                                            lblGuestID.Text & "','" &
                                            txtRoomNumber.Text & "','" &
                                            txtCheckInDate.Text & "','" &
                                            dtCheckOutDate.Text & "','" &
                                            txtChildren.Text & "','" &
                                            txtAdults.Text & "','" &
                                            txtAdvance.Text & "','" &
                                            lblDiscountID.Text & "','" &
                                            remarks & "','" &
                                            stat & "')", con)
            checkin.ExecuteNonQuery()

            Dim update_guest As New SqlCommand("UPDATE tblGuest SET Remarks = 'Checkin' WHERE ID = " & lblGuestID.Text & "", con)
            update_guest.ExecuteNonQuery()

            Dim update_room As New SqlCommand("UPDATE tblRoom SET Status = 'Occupied' WHERE