в 16:40, 26 мая 2010

2010-05-26T16:40:30Z

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2010-05-26T12:55:27Z

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==By value or by reference==

<source lang="vbnet">Option Strict On
Public Class YourClass
Public Name As String
Public GPA As Double
End Class
Public Structure YourStructure
Public Name As String
Public GPA As Double
End Structure
Public Class Test
Public Shared Sub Main()
Dim valueByRef As New YourClass()
Dim valueByValue As New YourStructure()
valueByRef.Name = "Jill"
valueByRef.GPA = 92.3
valueByValue.Name = "Jill"
valueByValue.GPA = 92.3
Dim ref2 As YourClass = valueByRef
Dim value2 As YourStructure = valueByValue
ref2.GPA += 2
value2.GPA += 2
Console.WriteLine("{0}"s GPA is: {1}", valueByRef.Name, valueByRef.GPA)
Console.WriteLine("{0}"s GPA is: {1}", valueByValue.Name, valueByValue.GPA)
End Sub
End Class</source>
<pre class=codeResult>Jill"s GPA is: 94.3
Jill"s GPA is: 92.3</pre>

==Class Vs Structure in ByValue and ByRef==

<source lang="vbnet">Imports System
Public Enum Country
US = 1
CA = 2
End Enum

Public Class AClass
Public Name As String
Public Status As Country
End Class
Public Structure AStruct
Public Name As String
Public Status As Country
End Structure
Public Module Test
Public Sub ChangeName_Obj_ByVal(ByVal details As AClass,ByVal NewName As String)
details.Name = NewName
End Sub
Public Sub ChangeName_Obj_ByRef(ByRef details As AClass,ByVal NewName As String)
details.Name = NewName
End Sub
Public Sub ChangeName_Struct_ByVal(ByVal details As AStruct,ByVal NewName As String)
details.Name = NewName
End Sub
Public Sub ChangeName_Struct_ByRef(ByRef details As AStruct,ByVal NewName As String)
details.Name = NewName
End Sub
Sub Main()
Dim classInstance As AClass = New AClass()
Dim structInstance As AStruct = New AStruct()
classInstance.Name = "A"
classInstance.Status = Country.CA
structInstance.Name = "B"
structInstance.Status = Country.CA
Console.WriteLine("{0}, {1}", classInstance.Name, classInstance.Status)
Console.WriteLine("{0}, {1}", structInstance.Name, structInstance.Status)
Console.WriteLine()
ChangeName_Obj_ByVal(classInstance, "AAAA")
ChangeName_Struct_ByVal(structInstance, "BBBB")

Console.WriteLine("{0},{1}", classInstance.Name, classInstance.Status)
Console.WriteLine("{0},{1}", structInstance.Name, structInstance.Status)
Console.WriteLine()
ChangeName_Obj_ByRef(classInstance, "AAAA")
ChangeName_Struct_ByRef(structInstance, "BBBB")
Console.WriteLine("{0}, {1}", classInstance.Name, classInstance.Status)
Console.WriteLine("{0}, {1}", structInstance.Name, structInstance.Status)
End Sub
End Module</source>
<pre class=codeResult>A, CA
B, CA
AAAA,CA
B,CA
AAAA, CA
BBBB, CA</pre>

==Define and use Structure==

<source lang="vbnet">Structure CheckRecord
Dim intCheckNumber As Integer
Dim dteCheckDate As Date
Dim sngCheckAmount As Single
Dim strCheckPaidTo As String
End Structure
public class Test
public Shared Sub Main
Dim udtCheck As CheckRecord
"Add data to the structure.
udtCheck.intCheckNumber = 275
udtCheck.dteCheckDate = #9/12/2001#
udtCheck.sngCheckAmount = 104.25
udtCheck.strCheckPaidTo = "Gas Co."
Console.WriteLine("CHECK INFORMATION")
Console.WriteLine("Number: " & udtCheck.intCheckNumber)
Console.WriteLine("Date: " & udtCheck.dteCheckDate)
Console.WriteLine("Amount: " & udtCheck.sngCheckAmount)
Console.WriteLine("Paid To: " & udtCheck.strCheckPaidTo)

End Sub
End class</source>
<pre class=codeResult>CHECK INFORMATION
Number: 275
Date: 12/09/2001
Amount: 104.25
Paid To: Gas Co.</pre>

==Define and use structure with modifier==

<source lang="vbnet">Option Strict On
Public Structure Coordinates
Public x As Double
Public y As Double
End Structure
Public Module Test
Public Sub Main()
Dim coord As Coordinates " The structure as a whole

coord.x = 10.2 " x member
coord.y = 25.1 " y member
Console.WriteLine(coord.ToString & ": x=" & coord.x & ", y=" & coord.y)
End Sub
End Module</source>
<pre class=codeResult>Coordinates: x=10.2, y=25.1</pre>

==Define Structure==

<source lang="vbnet">Option Strict On
Imports System
Public Structure Location
Private x As Integer
Private y As Integer
Public Sub New(ByVal xCoordinate As Integer, ByVal yCoordinate As Integer)
x = xCoordinate
y = yCoordinate
End Sub
Public Property XValue( ) As Integer
Get
Return x
End Get
Set(ByVal Value As Integer)
x = Value
End Set
End Property
Public Property YValue( ) As Integer
Get
Return y
End Get
Set(ByVal Value As Integer)
y = Value
End Set
End Property
Public Overrides Function ToString( ) As String
Return [String].Format("{0}, {1}", x, y)
End Function
End Structure
Class Tester
Public Shared Sub myFunc(ByVal loc As Location)
loc.XValue = 50
loc.YValue = 100
Console.WriteLine("Loc1 location: {0}", loc)
End Sub
Shared Sub Main( )
Dim loc1 As New Location(200, 300)
Console.WriteLine("Loc1 location: {0}", loc1)
Dim loc2 As New Location( )
Console.WriteLine("Loc2 location: {0}", loc2)
myFunc(loc1)
Console.WriteLine("Loc1 location: {0}", loc1)
End Sub
End Class</source>
<pre class=codeResult>Loc1 location: 200, 300
Loc2 location: 0, 0
Loc1 location: 50, 100
Loc1 location: 200, 300</pre>

==Structure==

<source lang="vbnet">Structure Money
Private centsAmount As Integer
Public Sub New(ByVal amount As Double)
Me.centsAmount = CInt(amount * 100)
End Sub
End Structure
Module MyModule
Sub Main()
Dim freebie As Money
Dim carPrice As Money = New Money(3.95)
End Sub
End Module</source>

==structure implements interface==

<source lang="vbnet">Imports System
Module MyModule
Sub Main()
Dim salaries(4) As Salary
salaries(0) = New Salary(9)
salaries(1) = New Salary(4)
salaries(2) = New Salary(8)
salaries(3) = salaries(2)
salaries(4) = New Salary(6)
Console.WriteLine("Unsorted array:")
Dim salary As Salary
For Each salary In salaries
Console.WriteLine("{0}", salary)
Next
Array.Sort(salaries)
Console.WriteLine(vbCrLf & "Sorted array:")
For Each salary In salaries
Console.WriteLine("{0}", salary)
Next
End Sub
End Module
Structure Salary
Implements IComparable
Private value As Integer
Public Sub New(ByVal amount As Double)
Me.value = CInt(amount * 100)
End Sub
Public Function CompareTo(ByVal other As Object) As Integer Implements IComparable.rupareTo
Dim m2 As Salary = CType(other, Salary)
If Me.value < m2.value Then
Return -1
ElseIf Me.value = m2.value Then
Return 0
Else
Return +1
End If
End Function
Public Overrides Function ToString() As String
Return Me.value
End Function
End Structure</source>
<pre class=codeResult>Unsorted array:
900
400
800
800
600
Sorted array:
400
600
800
800
900</pre>

==Use Structure as Function parameter==

<source lang="vbnet">public Structure CustomerBalance
Dim decBalSavings As Decimal
Dim decBalChecking As Decimal
End Structure

public class Test
public Shared Sub Main
Dim udtBalance As CustomerBalance

udtBalance = GetCustomerBalance(1)
Console.WriteLine(udtBalance.decBalChecking)
Console.WriteLine(udtBalance.decBalSavings)
End Sub
Shared Function GetCustomerBalance(ByVal intCustomerID As Integer) As CustomerBalance
Dim udtBalance As CustomerBalance
udtBalance.decBalChecking = CDec(1000 + 4000 * Rnd())
udtBalance.decBalSavings = CDec(1000 + 15000 * Rnd())
Return udtBalance
End Function

End class</source>
<pre class=codeResult>3822.19
9001.36</pre>

==Use With and Structure==

<source lang="vbnet">Imports System.Collections
Structure Person
Dim strLastName As String
Dim strFirstName As String
Dim strPhone As String
Dim strEMail As String
End Structure

public class Test
public Shared Sub Main
Dim alPersons As New ArrayList
Dim udtPerson As New Person
"Add the first person.
With udtPerson
.strLastName = "S"
.strFirstName = "J"
.strPhone = "5"
.strEMail = "j@s.ru"
End With
alPersons.Add(udtPerson)
"Add the second person.
With udtPerson
.strLastName = "J"
.strFirstName = "S"
.strPhone = "5"
.strEMail = "s@s.ru"
End With
alPersons.Add(udtPerson)
"Create the third person.
With udtPerson
.strLastName = "J"
.strFirstName = "K"
.strPhone = "5"
.strEMail = "k@s.ru"
End With
"Insert the third person, but first check if they already exists.
If Not alPersons.Contains(udtPerson) Then
alPersons.Insert(1, udtPerson)
End If
"Remove the first person.
alPersons.RemoveAt(0)
"Display the array list values.
Console.WriteLine("The array list contains " & alPersons.Count & " elements.")
For Each udtPerson In alPersons
Console.WriteLine("NAME: " & udtPerson.strFirstName & " " & udtPerson.strLastName)
Next udtPerson

End Sub
End class</source>
<pre class=codeResult>The array list contains 2 elements.
NAME: K J
NAME: S J</pre>

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