Writing Variables to a Pre-existing Array in VB.Net

I'm currently designing a mock-up of a customer booking system for a cinema using Framework 4.0. All data at present will be stored in an array and as it's a mock-up, it will remain their (customer name, ticket price etc...) as no requirement to permanently store the data at this time.

I have a GUI form and two main classes, MainForm.vb to handle the I/O features of the application and SeatManager.vb to manage the background methods that are to be run to make the program operate. The code for each class is as below:-

**MainForm.vb Class**
    Public Class MainForm
        Private Const m_totalNumberOfSeats As Integer = 60
        Private m_seatManager As SeatManager

        Public Sub New()

            InitializeComponent()
            m_seatManager = New SeatManager(m_totalNumberOfSeats)
            InitializeGUI()
        End Sub

        ''' <summary>
        ''' Method called from the MainForm() method. This method is called when the form
        ''' is opened by the program (on initialisation).
        ''' </summary>
        Private Sub InitializeGUI()
            rbtnReservation.Checked = True              'Sets the Reserve button as being chosen
            lstReservations.Items.Clear()               'Clears the list displaying all seats and reservations
            txtCustomerName.Text = String.Empty         'Sets the name textbox as emtpy
            txtSeatPrice.Text = String.Empty

            cmbDisplayOptions.Items.AddRange([Enum].GetNames(GetType(SeatManager.DisplayOptions)))
            cmbDisplayOptions.SelectedIndex = SeatManager.DisplayOptions.AllSeats

            For i As Integer = 0 To m_totalNumberOfSeats - 1
                lstReservations.Items.Add(GetMyString(i))
            Next
        End Sub
        Private Function GetMyString(ByVal i As Integer) As String
            If i >= 0 AndAlso i < m_totalNumberOfSeats Then
                Return String.Format("{0}{1}{2}{3}", GetPaddedString(m_seatManager.MyArray(i, 0), 29), _
                                     GetPaddedString(m_seatManager.MyArray(i, 1), 41), _
                                     GetPaddedString(m_seatManager.MyArray(i, 2), 63), _
                                     m_seatManager.MyArray(i, 3))
            Else
                Return String.Empty
            End If
        End Function

        Private Function GetPaddedString(ByVal o As Object, ByVal length As Integer) As String
            Dim s As String = String.Empty
            If o IsNot Nothing Then s = o.ToString()
            If s.Length > length Then s = s.Substring(0, length)
            Return s.PadRight(length - s.Length)
        End Function

        '--Event Handler when you change the value of Customer Name/Price
        '    Dim index As Integer = lstBox.selectedIndex
        'm_arrayClass.PopulateArray(index,customerName.text, ctype(price.text,double))
        'lstBox.Items(index) = GetMyString(index)

        'Private Function CheckSelectedIndex() As Boolean
        '    If lstReservations.SelectedIndex <= 0 Then
        '        Return lstReservations.SelectedIndex
        '    Else
        '        Return False
        '    End If
        'End Function

        ''' <summary>
        ''' Method uses to verify that the user has entered text within the txtName textbox
        ''' </summary>
        ''' <param name="name">String variable passing the customer name inputted by the user</param>
        ''' <returns>True if validation confirms user has entered at least one character in
        ''' the txtName field otherwise returns False. If returns false, an error message will
        ''' be displayed to the user</returns>
        Private Function ReadAndValidateName(ByRef name As String) As Boolean
            If (String.IsNullOrEmpty(txtCustomerName.Text)) Or (String.IsNullOrEmpty(txtCustomerName.Text)) Then
                MessageBox.Show("You have not entered a valid customer name. Please try again", _
                                "Invalid Customer Name", MessageBoxButtons.OK)
                txtCustomerName.Focus()
                txtCustomerName.SelectAll()
                Return False
            Else
                Return True
            End If
        End Function

        ''' <summary>
        ''' This method calls the GetDouble() method in the InputUtility class to convert the text
        ''' given by the user in the txtPrice textbox. 
        ''' </summary>
        ''' <param name="seatPrice">Output parameter receiving the converted value</param>
        ''' <returns>True if conversion is successful and validates or False. If returns False
        ''' an error message will be displayed to the user.</returns>
        Private Function ReadAndValidatePrice(ByRef seatPrice As Double) As Boolean
            If (InputUtility.GetDouble(txtSeatPrice.Text, seatPrice) And (seatPrice >= 0)) Then
                Return True
            Else
                MessageBox.Show("You have not entered a valid price. Please try again", _
                                "Invalid Price", MessageBoxButtons.OK)
                txtSeatPrice.Focus()
                txtSeatPrice.SelectAll()
                Return False
            End If
        End Function

        ''' <summary>
        ''' This method calls the above two methods (validate name and validate price) and if both return true, 
        ''' this method also returns true. If either of the above two methods are false, this method returns false
        ''' </summary>
        ''' <param name="name">Output Parameter - customer name</param>
        ''' <param name="seatPrice">Output parameter - seat price</param>
        ''' <returns>Returns true if validates and false if not</returns>
        Private Function ReadAndValidateInput(ByRef name As String, ByRef seatPrice As Double) As Boolean
            Dim nameResult As Boolean = ReadAndValidateName(name)
            Dim priceResult As Boolean = ReadAndValidatePrice(seatPrice)

            Return ((nameResult) And (priceResult))
        End Function

        Private Sub btnExitApplication_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExitApplication.Click

            Dim msgConfirmation As Integer
            msgConfirmation = MessageBox.Show("Are You Sure You Wish To Exit This Application?", "WARNING!", _
                                              MessageBoxButtons.YesNo, MessageBoxIcon.Exclamation)
            If msgConfirmation = vbYes Then
                Application.Exit()
            End If
        End Sub
    End Class




**SeatManager.vb Class**            
    Public Class SeatManager
        Private _array(,) As Object
        Dim m_totalNumberOfSeats As Integer

        Public Sub New(ByVal maxNumberOfSeats As Integer)
            m_totalNumberOfSeats = maxNumberOfSeats
            ReDim _array(m_totalNumberOfSeats - 1, 3)
            For i As Integer = 0 To m_totalNumberOfSeats - 1
                PopulateArray(i, Nothing, 0.0)
            Next
        End Sub

        Public ReadOnly Property MyArray() As Object(,)
            Get
                Return _array
            End Get
        End Property

        Public Enum DisplayOptions
            AllSeats
            VacantSeats
      开发者_开发技巧      ReservedSeats
        End Enum

        Public Sub PopulateArray(ByVal i As Integer, ByVal CustomerName As String, ByVal Price As Double)
            Dim av As String = "Available"
            If Not String.IsNullOrEmpty(CustomerName) Then av = "Not Available"
            'Did you say this has to be handled in an enum?

            _array(i, 0) = i + 1 'Seat Number
            _array(i, 1) = av
            _array(i, 2) = CustomerName
            _array(i, 3) = Price
        End Sub
    End Class

What I am looking to achieve now is, I have a textbox called, txtCustomerName and a textBox called txtPrice. When a user inputs a name and a price into these boxes and selects an entry in the listbox, lstReservations, I'd like the status to change from Available to "Reserved" and the Customer Name and Price to be intputted into the respective array fields.

Any suggestions? Thanks in advance

Here is a very easy way to implement an in-memory database using typed datasets and xml. You can create a typed dataset to hold your data in memory and even use a relational database structure to ensure data integrity. You can make changes in memory to this data and save the data to an XML file and reload that file on the next run, or you could just discard it and build it fresh on every run.

Here is some sample code for creating sample data and filling a dataset. You can write code to query the dataset at runtime like a real database.

    Dim SampleDataFileName = "c:\sampledata.xml"

    Dim ds As New dsReservations

    Try
        ds.ReadXml(SampleDataFileName)
    Catch ex As Exception

    End Try

    If ds.Event.Rows.Count = 0 Then
        'No data yet...initialize sample
        ds.Seat.AddSeatRow(1, "21B")
        ds.Seat.AddSeatRow(2, "21C")
        ds.Seat.AddSeatRow(3, "21D")

        ds.Customer.AddCustomerRow(1, "Bob")
        ds.Customer.AddCustomerRow(2, "Ed")
        ds.Customer.AddCustomerRow(3, "Sally")

        ds.Event.AddEventRow(1, #1/1/2012#, "Concert in the park")
        ds.Event.AddEventRow(2, #5/1/2012#, "Parade")



        Dim drRes1 = ds.Reservation.NewReservationRow
        drRes1.EventId = 1
        drRes1.SeatId = 2
        drRes1.CustomerId = 2
        ds.Reservation.AddReservationRow(drRes1)

        'Save our sample data
        ds.WriteXml(SampleDataFileName)
    End If

    'Spit out all our data (ASP.NET)'
    Response.Write(ds.GetXml())

Here is the dataset, name it "dsReservations.xsd". It has four related tables (Event,Seat,Customer & Reservation).

<?xml version="1.0" encoding="utf-8"?>
<xs:schema id="dsReservations" targetNamespace="http://tempuri.org/dsReservations.xsd" xmlns:mstns="http://tempuri.org/dsReservations.xsd" xmlns="http://tempuri.org/dsReservations.xsd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" xmlns:msprop="urn:schemas-microsoft-com:xml-msprop" attributeFormDefault="qualified" elementFormDefault="qualified">
  <xs:annotation>
    <xs:appinfo source="urn:schemas-microsoft-com:xml-msdatasource">
      <DataSource DefaultConnectionIndex="0" FunctionsComponentName="QueriesTableAdapter" Modifier="AutoLayout, AnsiClass, Class, Public" SchemaSerializationMode="IncludeSchema" xmlns="urn:schemas-microsoft-com:xml-msdatasource">
        <Connections />
        <Tables />
        <Sources />
      </DataSource>
    </xs:appinfo>
  </xs:annotation>
  <xs:element name="dsReservations" msdata:IsDataSet="true" msdata:UseCurrentLocale="true" msprop:Generator_DataSetName="dsReservations" msprop:Generator_UserDSName="dsReservations">
    <xs:complexType>
      <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="Customer" msprop:Generator_TableClassName="CustomerDataTable" msprop:Generator_TableVarName="tableCustomer" msprop:Generator_TablePropName="Customer" msprop:Generator_RowDeletingName="CustomerRowDeleting" msprop:Generator_UserTableName="Customer" msprop:Generator_RowChangingName="CustomerRowChanging" msprop:Generator_RowEvHandlerName="CustomerRowChangeEventHandler" msprop:Generator_RowDeletedName="CustomerRowDeleted" msprop:Generator_RowEvArgName="CustomerRowChangeEvent" msprop:Generator_RowChangedName="CustomerRowChanged" msprop:Generator_RowClassName="CustomerRow">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="CustomerId" msprop:Generator_ColumnVarNameInTable="columnCustomerId" msprop:Generator_ColumnPropNameInRow="CustomerId" msprop:Generator_ColumnPropNameInTable="CustomerIdColumn" msprop:Generator_UserColumnName="CustomerId" type="xs:int" />
              <xs:element name="CustomerName" msprop:Generator_ColumnVarNameInTable="columnCustomerName" msprop:Generator_ColumnPropNameInRow="CustomerName" msprop:Generator_ColumnPropNameInTable="CustomerNameColumn" msprop:Generator_UserColumnName="CustomerName" type="xs:string" minOccurs="0" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
        <xs:element name="Event" msprop:Generator_TableClassName="EventDataTable" msprop:Generator_TableVarName="tableEvent" msprop:Generator_TablePropName="Event" msprop:Generator_RowDeletingName="EventRowDeleting" msprop:Generator_UserTableName="Event" msprop:Generator_RowChangingName="EventRowChanging" msprop:Generator_RowEvHandlerName="EventRowChangeEventHandler" msprop:Generator_RowDeletedName="EventRowDeleted" msprop:Generator_RowEvArgName="EventRowChangeEvent" msprop:Generator_RowChangedName="EventRowChanged" msprop:Generator_RowClassName="EventRow">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="EventId" msprop:Generator_ColumnVarNameInTable="columnEventId" msprop:Generator_ColumnPropNameInRow="EventId" msprop:Generator_ColumnPropNameInTable="EventIdColumn" msprop:Generator_UserColumnName="EventId" type="xs:int" />
              <xs:element name="EventDate" msprop:Generator_ColumnVarNameInTable="columnEventDate" msprop:Generator_ColumnPropNameInRow="EventDate" msprop:Generator_ColumnPropNameInTable="EventDateColumn" msprop:Generator_UserColumnName="EventDate" type="xs:dateTime" minOccurs="0" />
              <xs:element name="EventName" msprop:Generator_ColumnVarNameInTable="columnEventName" msprop:Generator_ColumnPropNameInRow="EventName" msprop:Generator_ColumnPropNameInTable="EventNameColumn" msprop:Generator_UserColumnName="EventName" type="xs:string" minOccurs="0" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
        <xs:element name="Seat" msprop:Generator_TableClassName="SeatDataTable" msprop:Generator_TableVarName="tableSeat" msprop:Generator_TablePropName="Seat" msprop:Generator_RowDeletingName="SeatRowDeleting" msprop:Generator_UserTableName="Seat" msprop:Generator_RowChangingName="SeatRowChanging" msprop:Generator_RowEvHandlerName="SeatRowChangeEventHandler" msprop:Generator_RowDeletedName="SeatRowDeleted" msprop:Generator_RowEvArgName="SeatRowChangeEvent" msprop:Generator_RowChangedName="SeatRowChanged" msprop:Generator_RowClassName="SeatRow">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="SeatId" msprop:Generator_ColumnVarNameInTable="columnSeatId" msprop:Generator_ColumnPropNameInRow="SeatId" msprop:Generator_ColumnPropNameInTable="SeatIdColumn" msprop:Generator_UserColumnName="SeatId" type="xs:int" />
              <xs:element name="SeatLocation" msprop:Generator_ColumnVarNameInTable="columnSeatLocation" msprop:Generator_ColumnPropNameInRow="SeatLocation" msprop:Generator_ColumnPropNameInTable="SeatLocationColumn" msprop:Generator_UserColumnName="SeatLocation" type="xs:string" minOccurs="0" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
        <xs:element name="Reservation" msprop:Generator_TableClassName="ReservationDataTable" msprop:Generator_TableVarName="tableReservation" msprop:Generator_TablePropName="Reservation" msprop:Generator_RowDeletingName="ReservationRowDeleting" msprop:Generator_UserTableName="Reservation" msprop:Generator_RowChangingName="ReservationRowChanging" msprop:Generator_RowEvHandlerName="ReservationRowChangeEventHandler" msprop:Generator_RowDeletedName="ReservationRowDeleted" msprop:Generator_RowEvArgName="ReservationRowChangeEvent" msprop:Generator_RowChangedName="ReservationRowChanged" msprop:Generator_RowClassName="ReservationRow">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="EventId" msprop:Generator_ColumnVarNameInTable="columnEventId" msprop:Generator_ColumnPropNameInRow="EventId" msprop:Generator_ColumnPropNameInTable="EventIdColumn" msprop:Generator_UserColumnName="EventId" type="xs:int" />
              <xs:element name="SeatId" msprop:Generator_ColumnVarNameInTable="columnSeatId" msprop:Generator_ColumnPropNameInRow="SeatId" msprop:Generator_ColumnPropNameInTable="SeatIdColumn" msprop:Generator_UserColumnName="SeatId" type="xs:int" />
              <xs:element name="CustomerId" msprop:Generator_ColumnVarNameInTable="columnCustomerId" msprop:Generator_ColumnPropNameInRow="CustomerId" msprop:Generator_ColumnPropNameInTable="CustomerIdColumn" msprop:Generator_UserColumnName="CustomerId" type="xs:int" />
            </xs:sequence>
          </xs:complexType>
        </xs:element>
      </xs:choice>
    </xs:complexType>
    <xs:unique name="Constraint1" msdata:PrimaryKey="true">
      <xs:selector xpath=".//mstns:Customer" />
      <xs:field xpath="mstns:CustomerId" />
    </xs:unique>
    <xs:unique name="Event_Constraint1" msdata:ConstraintName="Constraint1" msdata:PrimaryKey="true">
      <xs:selector xpath=".//mstns:Event" />
      <xs:field xpath="mstns:EventId" />
    </xs:unique>
    <xs:unique name="Seat_Constraint1" msdata:ConstraintName="Constraint1" msdata:PrimaryKey="true">
      <xs:selector xpath=".//mstns:Seat" />
      <xs:field xpath="mstns:SeatId" />
    </xs:unique>
    <xs:unique name="Reservation_Constraint1" msdata:ConstraintName="Constraint1" msdata:PrimaryKey="true">
      <xs:selector xpath=".//mstns:Reservation" />
      <xs:field xpath="mstns:EventId" />
      <xs:field xpath="mstns:SeatId" />
    </xs:unique>
    <xs:unique name="Constraint2">
      <xs:selector xpath=".//mstns:Reservation" />
      <xs:field xpath="mstns:EventId" />
    </xs:unique>
    <xs:keyref name="FK_Event_Reservation" refer="Event_Constraint1" msprop:rel_Generator_UserChildTable="Reservation" msprop:rel_Generator_ChildPropName="GetReservationRows" msprop:rel_Generator_ParentPropName="EventRow" msprop:rel_Generator_UserRelationName="FK_Event_Reservation" msprop:rel_Generator_RelationVarName="relationFK_Event_Reservation" msprop:rel_Generator_UserParentTable="Event">
      <xs:selector xpath=".//mstns:Reservation" />
      <xs:field xpath="mstns:EventId" />
    </xs:keyref>
    <xs:keyref name="FK_Seat_Reservation" refer="Seat_Constraint1" msprop:rel_Generator_UserChildTable="Reservation" msprop:rel_Generator_ChildPropName="GetReservationRows" msprop:rel_Generator_ParentPropName="SeatRow" msprop:rel_Generator_UserRelationName="FK_Seat_Reservation" msprop:rel_Generator_RelationVarName="relationFK_Seat_Reservation" msprop:rel_Generator_UserParentTable="Seat">
      <xs:selector xpath=".//mstns:Reservation" />
      <xs:field xpath="mstns:SeatId" />
    </xs:keyref>
    <xs:keyref name="FK_Customer_Reservation" refer="Constraint1" msprop:rel_Generator_UserChildTable="Reservation" msprop:rel_Generator_ChildPropName="GetReservationRows" msprop:rel_Generator_ParentPropName="CustomerRow" msprop:rel_Generator_UserRelationName="FK_Customer_Reservation" msprop:rel_Generator_RelationVarName="relationFK_Customer_Reservation" msprop:rel_Generator_UserParentTable="Customer">
      <xs:selector xpath=".//mstns:Reservation" />
      <xs:field xpath="mstns:CustomerId" />
    </xs:keyref>
  </xs:element>
</xs:schema>

There are plenty of examples of how to query typed data tables out there. Enjoy!