form1.vb

Mastering VBNet Include Source Code

Imports System.io
Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents Button2 As System.Windows.Forms.Button

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.Container

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Button1 = New System.Windows.Forms.Button()
        Me.TextBox1 = New System.Windows.Forms.TextBox()
        Me.Button2 = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'Button1
        '
        Me.Button1.Font = New System.Drawing.Font("Verdana", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Button1.Location = New System.Drawing.Point(8, 8)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(264, 32)
        Me.Button1.TabIndex = 0
        Me.Button1.Text = "Save Records"
        '
        'TextBox1
        '
        Me.TextBox1.Font = New System.Drawing.Font("Verdana", 9.0!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.TextBox1.Location = New System.Drawing.Point(8, 88)
        Me.TextBox1.Multiline = True
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.ScrollBars = System.Windows.Forms.ScrollBars.Vertical
        Me.TextBox1.Size = New System.Drawing.Size(264, 176)
        Me.TextBox1.TabIndex = 1
        Me.TextBox1.Text = ""
        '
        'Button2
        '
        Me.Button2.Enabled = False
        Me.Button2.Font = New System.Drawing.Font("Verdana", 9.75!, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Button2.Location = New System.Drawing.Point(8, 48)
        Me.Button2.Name = "Button2"
        Me.Button2.Size = New System.Drawing.Size(264, 32)
        Me.Button2.TabIndex = 2
        Me.Button2.Text = "Read Records"
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(280, 269)
        Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Button2, Me.TextBox1, Me.Button1})
        Me.Name = "Form1"
        Me.Text = "StreamWriter/Reader Demo"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Structure Product
        Dim ProdID As String
        Dim prodDescription As String
        Dim listPrice As Single
        Dim Available As Boolean
        Dim minStock As Integer
    End Structure

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim BW As BinaryWriter
        Dim FS As FileStream
        FS = New FileStream("BinaryData.bin", _
                            System.IO.FileMode.OpenOrCreate, _
                            System.IO.FileAccess.Write)
        BW = New BinaryWriter(FS)
        BW.BaseStream.Seek(0, SeekOrigin.Begin)

        Dim p As New Product()
        p.ProdID = "100-A39"
        p.prodDescription = "Cellular Phone with built-in TV"
        p.listPrice = 497.99
        p.available = True
        p.minStock = 40
        SaveRecord(BW, p)

        p = New Product()
        p.ProdID = "100-U300"
        p.prodDescription = "Wireless Handheld"
        p.listPrice = 315.5
        p.Available = False
        p.minStock = 12
        SaveRecord(BW, p)

        p = New Product()
        p.ProdID = "99-BBB"
        p.prodDescription = "Calculator/Recorder Watch"
        p.listPrice = 49.99
        p.available = True
        p.minStock = 10
        SaveRecord(BW, p)

        BW.Close()
        FS.Close()
        FS = Nothing
        MsgBox("Records saved")
        Button2.Enabled = True
    End Sub

    Sub SaveRecord(ByVal writer As BinaryWriter, ByVal record As Product)
        writer.Write(record.ProdID)
        writer.Write(record.prodDescription)
        writer.Write(record.listPrice)
        writer.Write(record.Available)
        writer.Write(record.minStock)
    End Sub

    Sub ShowRecord(ByVal record As Product)
        TextBox1.AppendText(vbCrLf)
        TextBox1.AppendText(record.prodDescription & vbCrLf)
        TextBox1.AppendText(record.listPrice.ToString & vbCrLf)
        TextBox1.AppendText(record.Available & vbCrLf)
        TextBox1.AppendText(record.minStock.ToString & vbCrLf)
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim BR As BinaryReader
        Dim FS As FileStream
        FS = New System.IO.FileStream("Binarydata.bin", _
                                      FileMode.Open, _
                                      FileAccess.Read)
        BR = New System.IO.BinaryReader(FS)
        BR.BaseStream.Seek(0, SeekOrigin.Begin)
        Dim p As New Product()
        TextBox1.Clear()
        Dim c As Integer
        c = BR.PeekChar
        While FS.Position < FS.Length

            Console.WriteLine(c)
            p = Nothing
            '   READ FIELDS AND POPULATE STRUCTURE 
            p.ProdID = BR.ReadString
            p.prodDescription = BR.ReadString
            p.listPrice = BR.ReadSingle
            p.Available = BR.ReadBoolean
            p.minStock = BR.ReadInt32
            '   DISPLAY STRUCTURE   
            ShowRecord(p)
            c = BR.PeekChar
        End While
        BR.Close()
        FS.Close()
    End Sub

End Class