Visual Basic.NET How to Program (PDF)

Chapter 17 Files and Streams 791
1 ' Fig. 17.14: CRandomAccessRecord.vb
2 ' Data-record class for random-access applications.
3
4 Public Class CRandomAccessRecord
5
6 ' length of recordFirstName and recordLastName
7 Private Const CHAR_ARRAY_LENGTH As Integer = 15
8
9 Private Const SIZE_OF_CHAR As Integer = 2
10 Private Const SIZE_OF_INT32 As Integer = 4
11 Private Const SIZE_OF_DOUBLE As Integer = 8
12
13 ' length of record
14 Public Const SIZE As Integer = SIZE_OF_INT32 + _
15 2 * (SIZE_OF_CHAR * CHAR_ARRAY_LENGTH) + SIZE_OF_DOUBLE
16
17 ' record data
18 Private mAccount As Integer
19 Private mFirstName(CHAR_ARRAY_LENGTH) As Char
20 Private mLastName(CHAR_ARRAY_LENGTH) As Char
21 Private mBalance As Double
22
23 ' default constructor sets members to default values
24 Public Sub New()
25 Me.New(0, "", "", 0.0)
26 End Sub ' New
27
28 ' overloaded constructor sets members to parameter values
29 Public Sub New(ByVal accountValue As Integer, _
30 ByVal firstNameValue As String, _
31 ByVal lastNameValue As String, _
32 ByVal balanceValue As Double)
33
34 Account = accountValue
35 FirstName = firstNameValue
36 LastName = lastNameValue
37 Balance = balanceValue
38 End Sub ' New
39
40 ' property Account
41 Public Property Account() As Integer
42
43 Get
44 Return mAccount
45 End Get
46
47 Set(ByVal accountValue As Integer)
48 mAccount = accountValue
49 End Set
50
51 End Property ' Account
52
Fig. 17.14 CRandomAccessRecord class represents a record for random-access
file-processing applications (part 1 of 3).