kurs vba Statements 4

4.Statements

4.1.If

4.1.1.If with And

Imports System

Public Class Test

     Shared Sub Main()
        Dim dtCurrent As System.DateTime
        Dim iHour As Integer

        dtCurrent = dtCurrent.Now()
        iHour = dtCurrent.Hour

        If (iHour < 12) Then
            Console.Writeline("Good Morning!")
        ElseIf (iHour >= 12) And (iHour < 18) Then
            Console.WriteLine("Good Afternoon!")
        Else
            Console.WriteLine("Good Evening!")
        End If
    End Sub

End Class

 
Good Afternoon!

4.1.2.Use if statement to compare Integer

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim valueOne As Integer = 10
       Dim valueTwo As Integer = 20
       Dim valueThree As Integer = 30

       If valueOne > valueTwo Then
          Console.WriteLine("ValueOne: {0} larger than ValueTwo: {1}", valueOne, valueTwo)
       End If

       If valueThree > valueTwo Then
          Console.WriteLine("ValueThree: {0} larger than ValueTwo: {1}",valueThree, valueTwo)
       End If

       If valueTwo > 15 Then 
            Console.WriteLine("Yes it is")
       End If
    End Sub 'Main
 End Module

 
ValueThree: 30 larger than ValueTwo: 20
Yes it is

4.1.3.Nested if statement

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim temp As Integer = 32

       If temp <= 32 Then

          If temp = 32 Then
             Console.WriteLine("temp = 32")
          Else
             Console.WriteLine("Temp: {0}", temp)
          End If
       End If 
    End Sub 

 End Module

 
temp = 32

4.1.4.Use ElseIf

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim temp As Integer = -32

       If temp > 32 Then
       ElseIf temp = 32 Then
          Console.WriteLine("= 32")
       ElseIf temp > 0 Then
       ElseIf temp = 0 Then
          Console.WriteLine(" = 0")
       Else
          Console.WriteLine("Else")
       End If
    End Sub 'Main

 End Module

 
Else

4.1.5.Else If (Not ELSEIF)

Imports System

Public Class Test

     Shared Sub Main()
        Dim dtCurrent As System.DateTime
        Dim iHour As Integer

        dtCurrent = dtCurrent.Now()
        iHour = dtCurrent.Hour

        If (iHour < 12) Then
            Console.Writeline("Good Morning!")
        Else If (iHour >= 12) And (iHour < 18) Then
               Console.WriteLine("Good Afternoon!")
        Else
            Console.WriteLine("Good Evening!")
        End If
    End Sub

End Class

 
Very Good.

4.1.6.Use If statement in a For statement

public class Test
   public Shared Sub Main

        Dim intCounter As Integer
        Dim strString As String = "some silly string"

        For intCounter = 0 To strString.Length - 1
            If strString(intCounter) = "s" Then
                strString = strString.Remove(intCounter, 1)
                strString = strString.Insert(intCounter, "S")
            End If
        Next intCounter
        Console.WriteLine(strString)

   End Sub


End class

 
Some Silly String

4.1.7.ElseIf

public class Test
   public Shared Sub Main

        Dim intScore As Integer
        Dim strResult As String

        intScore = 78

        If intScore < 50 Then
            strResult = "Failed."
        ElseIf intScore < 75 Then
            strResult = "Pass."
        ElseIf intScore < 90 Then
            strResult = "Very Good."
        Else
            strResult = "Excellent."
        End If
        Console.WriteLine(strResult)


   End Sub


End class

 
Very Good.

4.1.8.Single line vs Multi-line If statement

public class Test
   public Shared Sub Main

        Dim intScore As Integer

        intScore = 23

        'Single line If statement.
        If intScore < 50 Then Console.WriteLine("Failed.") : Console.WriteLine("Please try again.")


        'Multi-line If statement.
        If intScore < 50 Then
            Console.WriteLine("Failed.")
            Console.WriteLine("Please try again.")
        End If

   End Sub


End class

 
Failed.
Please try again.
Failed.
Please try again.


4.1.9.If statement Short Circuiting

Public Class ShortCircuiting
     Shared Sub Main()
         If Test("Left") AND Test("Right") Then
             'do something
         End If
     End Sub
 
     Shared Function Test(sInput As String) As Boolean
         System.Console.WriteLine(sInput)
         Test = FALSE
     End Function
End Class

 


Left
Right

4.1.10.If Short Circuiting with ANDALSO

Public Class ShortCircuiting
     Shared Sub Main()
         If Test("Left") ANDALSO Test("Right") Then
             'do something
         End If
     End Sub
 
     Shared Function Test(sInput As String) As Boolean
         System.Console.WriteLine(sInput)
         Test = FALSE
     End Function
End Class

 
Left

4.2.IIf

4.2.1.IIf

public class Test
   public Shared Sub Main

        Dim intScore As Integer

        intScore = 23

        Console.WriteLine( IIf((intScore < 50), 1, 2) )

   End Sub


End class

 
1

4.3.Select

4.3.1.Using Select Case structure

Module Tester

   Sub Main()
      Dim grade As Integer = 89  
      Dim aCount As Integer = 0 
      Dim bCount As Integer = 0 
      Dim cCount As Integer = 0 
      Dim dCount As Integer = 0 
      Dim fCount As Integer = 0 

      Select Case grade    
         Case 100          
            Console.WriteLine("Perfect Score!" & vbCrLf & "Letter grade: A" & vbCrLf)
            aCount += 1

         Case 90 To 99     
            Console.WriteLine("Letter Grade: A" & vbCrLf)
            aCount += 1

         Case 80 To 89     
            Console.WriteLine("Letter Grade: B" & vbCrLf)
            bCount += 1

         Case 70 To 79     
            Console.WriteLine("Letter Grade: C" & vbCrLf)
            cCount += 1

         Case 60 To 69     
            Console.WriteLine("Letter Grade: D" & vbCrLf)
            dCount += 1

         Case 0, 10 To 59
            Console.WriteLine("Letter Grade: F" & vbCrLf)
            fCount += 1

         Case Else
            Console.WriteLine("Invalid Input. " & _
               "Please enter a valid grade." & vbCrLf)
      End Select

   End Sub  

End Module

 
Letter Grade: B

4.3.2.Select Case statement with Integer and exact value

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim targetInteger As Integer = 15

       Select Case targetInteger
          Case 5
             Console.WriteLine("5")
          Case 10
             Console.WriteLine("10")
          Case 15
             Console.WriteLine("15!")
          Case Else
             Console.WriteLine("Value not found")
       End Select
    End Sub 'Main

 End Module

 
15!

4.3.3.Select Case statement with range Integer value

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim targetInteger As Integer = 7

       Select Case targetInteger
          Case Is < 10
             Console.WriteLine("Less than 10")
          Case 10 To 14
             Console.WriteLine("10-14")
          Case 15
             Console.WriteLine("15!")
          Case Else
             Console.WriteLine("Value not found")
       End Select
    End Sub 'Main

 End Module

 
Less than 10

4.3.4.Select Case statement with String range value

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim target As String = "M"
       Select Case target

          Case "A" To "L"
             Console.WriteLine("A To L executed")
          Case "L" To "Z"
             Console.WriteLine("L To Z executed")
          Case Else
             Console.WriteLine("Else executed")
       End Select
    End Sub 'Main

 End Module

 
L To Z executed

4.3.5.Select Now.DayOfWeek

public class Test
   public Shared Sub Main


        Dim strMessage As String

        Select Case Now.DayOfWeek
            Case DayOfWeek.Monday
                strMessage = "Have a nice week."
            Case DayOfWeek.Friday
                strMessage = "Have a nice weekend."
            Case Else
                strMessage = "Welcome back!"
        End Select
        Console.WriteLine(strMessage)

   End Sub


End class

 
Have a nice weekend.

4.3.6.Use both range and fix value in Select statement

Module Module1

    Sub Main()
        Dim intInput As Integer = 12
        
        
        Select Case intInput
            Case 1
                Console.WriteLine("Thank you for the 1.")
            Case 2 To 5
                Console.WriteLine("Your value was 2, 3, 4, or 5")
            Case Is > 5
                Console.WriteLine("That was greater than 5.")
            Case Else
                Console.WriteLine("Sorry, I can't deal with that.")
        End Select
    End Sub

End Module

 
That was greater than 5.

4.3.7.Specify several values in one Case statement

public class Test
   public Shared Sub Main
        Select Case "Bird"
            Case "Bird"
                Console.WriteLine("This animal has 2 legs.")
            Case "Horse", "Dog", "Cat"
                Console.WriteLine("This animal has 4 legs.")
            Case "Snake"
                Console.WriteLine("This animal has no legs.")
            Case "Centipede"
                Console.WriteLine("This animal has 100 legs.")
            Case Else
                Console.WriteLine("You did not select from the list!")
        End Select

   End Sub
End Class

 
This animal has 2 legs.

4.4.Switch

4.4.1.Microsoft.VisualBasic.Switch

Module Module1

    Sub Main()
        Dim intValue As Integer = -10


        Console.WriteLine("Absolute value: " & _
            Microsoft.VisualBasic.Switch(intValue < 0, -1 * intValue, intValue >= 0, intValue))
    End Sub

End Module

 
Absolute value: 10

4.5.With statement

4.5.1.Use With statement with Form object

Imports System.Drawing
Imports System.Windows.Forms

Public Class WithForm : Inherits Form
   Public Shared Sub Main()
      Dim frm as New Form
      With frm
         .BackColor = Color.Gray
         .ForeColor = Color.Red
         .Text = "The With Statement"
         .Enabled = True
         .Topmost = True
         .MinimizeBox = False
         .ShowDialog()
      End With
   End Sub
End Class

4.5.2.Insert statement into With statement

Imports System.Drawing
Imports System.Windows.Forms

Public Class WithForm : Inherits Form
   Public Shared Sub Main()

      Dim frm as New Form
      With frm
         .BackColor = Color.Gray
         .ForeColor = Color.Red
         .Text = "The With Statement"
          Dim fnt As Font = .Font
          MsgBox(fnt.Name)
         .Enabled = True
         .Topmost = True
         .MinimizeBox = False
         .ShowDialog()
      End With
   End Sub
End Class

4.5.3.Nested With statement

Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1 : Inherits Form
   Public Shared Sub Main()
      Dim frm As New Form1()
      Application.Run(frm)
   End Sub

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
      With Me
         .BackColor = Color.Gray
         .ForeColor = Color.Red
         .Text = "The With Statement"
         .Enabled = True
         .TopMost = True
         .MinimizeBox = False
         For Each ctrl As Control In .Controls
            With ctrl
               .BackColor = SystemColors.Window
               .AutoSize = False
               .Cursor = Cursors.Hand
            End With
         Next
      End With
   End Sub
End Class

4.5.4.Use With statement with OpenFileDialog

Imports System.Windows.Forms

public class OpenFileDialogWith
   public Shared Sub Main
        Dim OpenFileDialog1 As OpenFileDialog = New System.Windows.Forms.OpenFileDialog
        With OpenFileDialog1
            .FileName = "C:\My Documents\Doc1.txt"
            .DefaultExt = ".txt"
            .Filter = "Text Files|*.TXT"
            .Filter = "Bitmaps|*.BMP|GIF Images|*.GIF|" & _
               "JPG Images|*.JPG|All Images|*.BMP;*.GIF;*.JPG"
            .FilterIndex = 2
            .InitialDirectory = "C:\My Documents"
            .ShowReadOnly = True
            .ReadOnlyChecked = True
        End With

        If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
            Console.WriteLine(OpenFileDialog1.FileName)
            
        End If


   End Sub
End class


4.6.For

4.6.1.For To Next Loop

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim loopCounter As Integer
       For loopCounter = 0 To 9
          Console.WriteLine("loopCounter: {0}", loopCounter)
       Next

    End Sub

 End Module

 
loopCounter: 0
loopCounter: 1
loopCounter: 2
loopCounter: 3
loopCounter: 4
loopCounter: 5
loopCounter: 6
loopCounter: 7
loopCounter: 8
loopCounter: 9

4.6.2.Using For/Next structure to demonstrate summation.

Imports System.Windows.Forms

Module Tester

    Sub Main()
        Dim sum = 0, number As Integer

        ' add even numbers from 2 to 100
        For number = 2 To 100 Step 2
         sum += number
        Next

      Console.WriteLine("The sum is " & sum & "Sum even integers from 2 to 100")
    End Sub 

End Module

 
The sum is 2550Sum even integers from 2 to 100

4.6.3.Calculating compound interest.

Module Tester

   Sub Main()
      Dim amount, principal As Decimal 
      Dim rate As Double               
      Dim year As Integer              
      Dim output As String             

      principal = 1000
      rate = 0.05

      output = "Year" & vbTab & "Amount on deposit" & vbCrLf

      For year = 1 To 10
         amount = principal * (1 + rate) ^ year
         output &= year & vbTab & _
            String.Format("{0:C}", amount) & vbCrLf
      Next

      Console.WriteLine(output)
   End Sub  

End Module

 
Year    Amount on deposit
1       $1,050.00
2       $1,102.50
3       $1,157.63
4       $1,215.51
5       $1,276.28
6       $1,340.10
7       $1,407.10
8       $1,477.46
9       $1,551.33
10      $1,628.89

4.6.4.For loop with float point control number

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim loopCounter As Single
       For loopCounter = 0.5 To 9
          Console.WriteLine("loopCounter: {0}", loopCounter)
       Next

    End Sub 'Main

 End Module

 
loopCounter: 0.5
loopCounter: 1.5
loopCounter: 2.5
loopCounter: 3.5
loopCounter: 4.5
loopCounter: 5.5
loopCounter: 6.5
loopCounter: 7.5
loopCounter: 8.5

4.6.5.Set For Loop float Step

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim loopCounter As Single
       For loopCounter = 0.5 To 9 Step 0.5
          Console.WriteLine("loopCounter: {0}", loopCounter)
       Next

    End Sub 'Main

 End Module

 
loopCounter: 0.5
loopCounter: 1
loopCounter: 1.5
loopCounter: 2
loopCounter: 2.5
loopCounter: 3
loopCounter: 3.5
loopCounter: 4
loopCounter: 4.5
loopCounter: 5
loopCounter: 5.5
loopCounter: 6
loopCounter: 6.5
loopCounter: 7
loopCounter: 7.5
loopCounter: 8
loopCounter: 8.5
loopCounter: 9

4.6.6.Nested For Loop

Option Strict On
 Imports System
 Module Module1

    Sub Main( )

       Dim outer As Integer
       Dim inner As Integer

       For outer = 3 To 6
          For inner = 10 To 12
             Console.WriteLine("{0} * {1} = {2}", _
                 outer, inner, outer * inner)
       Next inner, outer

    End Sub 'Main

 End Module

 
3 * 10 = 30
3 * 11 = 33
3 * 12 = 36
4 * 10 = 40
4 * 11 = 44
4 * 12 = 48
5 * 10 = 50
5 * 11 = 55
5 * 12 = 60
6 * 10 = 60
6 * 11 = 66
6 * 12 = 72

4.6.7.Float step

public class Test
   public Shared Sub Main
        For x As Single = 1 To 3 Step 0.5
            Console.WriteLine(x.ToString("0.0"))
        Next x

   End Sub

End class

 
1.0
1.5
2.0
2.5
3.0

4.6.8.Calculated step

public class Test
   public Shared Sub Main
        For x As Single = 1 To 2 Step 1 / 7
            Console.WriteLine(x)
        Next x

   End Sub

End class

 
1
1.142857
1.285714
1.428572
1.571429
1.714286
1.857143

4.6.9.Exit For 1

public class Test
   public Shared Sub Main
        Dim j As Integer
        For i As Integer = 1 To 3
            j = 0
            Do While j < 3
                j += 1
                For k As Integer = 1 To 3
                    Dim test1 As Boolean = k = 2
                    If test1 Then Exit For ' Exits the For K loop.

                    Dim test2 As Boolean = i = j
                    If test2 Then Exit Do ' Exits the Do.

                    Console.WriteLine(i & ", " & j & ", " & k)
                Next k
            Loop
        Next i
   End Sub

End class

 
2, 1, 1
3, 1, 1
3, 2, 1

4.7.For Each

4.7.1.Use For Each to loop through Array

Option Strict On
 Imports System

 Public Class Employee
     Private empID As Integer
     Public Sub New(ByVal empID As Integer)
         Me.empID = empID
     End Sub 

     Public Overrides Function ToString( ) As String
         Return empID.ToString( )
     End Function 
 End Class 
 
 
 Class Tester

     Shared Sub Main( )
    
         Dim intArray( ) As Integer
         Dim empArray( ) As Employee
         intArray = New Integer(5) {}
         empArray = New Employee(3) {}
    
         Dim i As Integer
         For i = 0 To empArray.Length - 1
             empArray(i) = New Employee(i + 5)
         Next i
    
         Console.WriteLine("The Integer array...")
         Dim intValue As Integer
         For Each intValue In intArray
             Console.WriteLine(intValue.ToString( ))
         Next
    
         Console.WriteLine("The employee array...")
         Dim e As Employee
         For Each e In empArray
             Console.WriteLine(e)
         Next
     End Sub 'Run
 End Class

 
The Integer array...
0
0
0
0
0
0
The employee array...
5
6
7
8

4.7.2.For Each with Collection

Imports System.Collections


public class Test
   public Shared Sub Main
        Dim m_employees As New Collection
        m_employees.Add(New employee("A", "F", "F"))
        m_employees.Add(New employee("B", "E", "H"))
        m_employees.Add(New employee("C", "D", "I"))


        For Each emp1 As employee In m_employees
            If emp1.FirstName = "A" Then Continue For
            Console.WriteLine(emp1.Title & " " & emp1.FirstName & " " & emp1.LastName)
        Next emp1

   End Sub

End class

    
Public Class Employee
    Public FirstName As String
    Public LastName As String
    Public Title As String
    Public Sub New(ByVal first_name As String, ByVal last_name As String, ByVal new_title As String)
        FirstName = first_name
        LastName = last_name
        Title = new_title
    End Sub
End Class

 
H B E
I C D

4.8.While

4.8.1.While structure

Module Tester
    Sub Main()
        Dim product As Integer = 2


        While product <= 1000
            Console.Write("{0}  ", product)
            product = product * 2
        End While

        Console.WriteLine("Smallest power of 2 " & _
           "greater than 1000 is {0}", product)
    End Sub ' Main

End Module

 
2  4  8  16  32  64  128  256  512  Smallest power of 2 greater than 1000 is 1024

4.8.2.Using counter-controlled repetition

Module modAverage

    Sub Main()
        Dim total As Integer         
        Dim gradeCounter As Integer  
        Dim grade As Integer         
        Dim average As Double        

        total = 0                    
        gradeCounter = 1             

        While gradeCounter <= 10
            grade = 12

            total += grade    

            gradeCounter += 1 
        End While

        average = total / 10

        Console.WriteLine("Class average is {0}", average)

    End Sub 

End Module

 
Class average is 12

4.8.3.Draw square of * by using nested while loop

Module Tester

   Sub Main()
      Dim side As Integer    
      Dim row As Integer = 1 
      Dim column As Integer  

      side = 12

      If side <= 20 Then 
         While row <= side 
            column = 1
            While column <= side
               Console.Write("* ") 
               column += 1         
            End While

            Console.WriteLine() 
            row += 1            
         End While
      Else 
         Console.WriteLine("Side too large")
      End If

   End Sub

End Module

 
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *
* * * * * * * * * * * *

4.8.4.Combine While and If to search in an array

Imports System

Public Class WhileExample

    Shared Sub Main()
        Dim iCounter As Integer = 0
        Dim arrList(9) As String
        Dim iMatch As Integer = -1
        Dim sMatch As String

        sMatch = "A"
        arrList(0) = "A"
        arrList(1) = "B"
        arrList(2) = "C"
        arrList(3) = "D"
        arrList(4) = "E"
        arrList(5) = "G"
        arrList(6) = "H"
        arrList(7) = "I"
        arrList(8) = "J"
        arrList(9) = "K"

        While iCounter <= 9 AND iMatch = -1
            If arrList(iCounter) Like sMatch Then
                iMatch = iCounter
            Else
                iCounter = iCounter + 1
            End If
        End While

        If iMatch <> -1 Then
            System.Console.WriteLine("Matched " & iMatch)
        End If

    End Sub
End Class

4.9.Do Loop Until

4.9.1.Using Do/Loop Until repetition structure

Module Tester

   Sub Main()
      Dim counter As Integer = 1

      Do
         Console.Write(counter & " ")
         counter += 1
      Loop Until counter > 5

   End Sub 

End Module

 
1 2 3 4 5 "

4.10.Do Loop While

4.10.1.Demonstrating the Do/Loop While repetition structure.

Module Tester

    Sub Main()
        Dim counter As Integer = 1

        Do
            Console.Write(counter & " ")
            counter += 1
      Loop While counter <= 5

    End Sub

End Module

 
1 2 3 4 5

4.11.Do Until

4.11.1.Do Until Loop

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim counterVariable As Integer = 0

       Do Until counterVariable = 10
          Console.WriteLine("counterVariable: {0}", counterVariable)
          counterVariable = counterVariable + 1
       Loop 

    End Sub

 End Module

 
counterVariable: 0
counterVariable: 1
counterVariable: 2
counterVariable: 3
counterVariable: 4
counterVariable: 5
counterVariable: 6
counterVariable: 7
counterVariable: 8
counterVariable: 9

4.11.2.Do Until/Loop (2)

Module Tester

    Sub Main()
        Dim product As Integer = 2

        Do Until product > 1000
            Console.Write("{0}  ", product)
            product = product * 2
        Loop

        Console.WriteLine("Smallest power of 2 " & _
           "greater than 1000 is {0}", product)
    End Sub 

End Module

 
2  4  8  16  32  64  128  256  512  Smallest power of 2 greater than 1000 is 1024

4.12.Do While

4.12.1.Do While Loop

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim counterVariable As Integer = 0

       Do While counterVariable < 10
          Console.WriteLine("counterVariable: {0}", counterVariable)
          counterVariable = counterVariable + 1
       Loop 

    End Sub 
 End Module

 
counterVariable: 0
counterVariable: 1
counterVariable: 2
counterVariable: 3
counterVariable: 4
counterVariable: 5
counterVariable: 6
counterVariable: 7
counterVariable: 8
counterVariable: 9

4.12.2.Do While/Loop: multiplies and displays product while product is less than or equal to 1000

Module Tester

    Sub Main()
        Dim product As Integer = 2

        
        Do While product <= 1000
            Console.Write("{0}  ", product)
            product = product * 2
        Loop

        Console.WriteLine("Smallest power of 2 " & _
           "greater than 1000 is {0}", product)
    End Sub

End Module

 
2  4  8  16  32  64  128  256  512  Smallest power of 2 greater than 1000 is 1024

4.12.3.Exit Do While

public class Test
   public Shared Sub Main
        Dim j As Integer
        For i As Integer = 1 To 3
            j = 0
            Do While j < 3
                j += 1
                For k As Integer = 1 To 3
                    Dim test1 As Boolean = k = 2
                    If test1 Then Exit For ' Exits the For K loop.

                    Dim test2 As Boolean = i = j
                    If test2 Then Exit Do ' Exits the Do.

                    Console.WriteLine(i & ", " & j & ", " & k)
                Next k
            Loop
        Next i
   End Sub

End class

 
2, 1, 1
3, 1, 1
3, 2, 1

4.14.Continue

4.14.1.Continue Do

public class Test
   public Shared Sub Main
        Dim j As Integer
        For i As Integer = 1 To 3
            j = 0
            Do While j < 3
                j += 1
                For k As Integer = 1 To 3
                    Dim test1 As Boolean = k = 2
                    If test1 Then Continue For ' Continues the For K loop.

                    Dim test2 As Boolean = i = j
                    If test2 Then Continue Do ' Continues the Do.

                    Console.WriteLine(i & ", " & j & ", " & k)
                Next k
            Loop
        Next i
   End Sub

End class

 
1, 2, 1
1, 2, 3
1, 3, 1
1, 3, 3
2, 1, 1
2, 1, 3
2, 3, 1
2, 3, 3
3, 1, 1
3, 1, 3
3, 2, 1
3, 2, 3

4.14.2.Continue For

Option Strict On

Public Module ContinueStatement
   Public Sub Main()
      For ctr As Integer = 1 to 100
         If ctr Mod 2 = 1 Then
            Console.Write("{0} is odd", ctr)
         Else
            Console.WriteLine("{0} is even.", ctr)
            Continue For
         End If
         If ctr Mod 3 = 0 Then
            Console.Write(" and it is divisible by 3")
         End If
         If ctr Mod 5 = 0 Then
            Console.Write(" and it is divisible by 5")
         End If
         If ctr Mod 7 = 0 Then
            Console.Write(" and it is divisible by 7")
         End If
         Console.WriteLine()
      Next
   End Sub
End Module

 
1 is odd
2 is even.
3 is odd and it is divisible by 3
4 is even.
5 is odd and it is divisible by 5
6 is even.
7 is odd and it is divisible by 7
8 is even.
9 is odd and it is divisible by 3
10 is even.
11 is odd
12 is even.
13 is odd
14 is even.
15 is odd and it is divisible by 3 and it is divisible by 5
16 is even.
17 is odd
18 is even.
19 is odd
20 is even.
21 is odd and it is divisible by 3 and it is divisible by 7
22 is even.
23 is odd
24 is even.
25 is odd and it is divisible by 5
26 is even.
27 is odd and it is divisible by 3
28 is even.
29 is odd
30 is even.
31 is odd
32 is even.
33 is odd and it is divisible by 3
34 is even.
35 is odd and it is divisible by 5 and it is divisible by 7
36 is even.
37 is odd
38 is even.
39 is odd and it is divisible by 3
40 is even.
41 is odd
42 is even.
43 is odd
44 is even.
45 is odd and it is divisible by 3 and it is divisible by 5
46 is even.
47 is odd
48 is even.
49 is odd and it is divisible by 7
50 is even.
51 is odd and it is divisible by 3
52 is even.
53 is odd
54 is even.
55 is odd and it is divisible by 5
56 is even.
57 is odd and it is divisible by 3
58 is even.
59 is odd
60 is even.
61 is odd
62 is even.
63 is odd and it is divisible by 3 and it is divisible by 7
64 is even.
65 is odd and it is divisible by 5
66 is even.
67 is odd
68 is even.
69 is odd and it is divisible by 3
70 is even.
71 is odd
72 is even.
73 is odd
74 is even.
75 is odd and it is divisible by 3 and it is divisible by 5
76 is even.
77 is odd and it is divisible by 7
78 is even.
79 is odd
80 is even.
81 is odd and it is divisible by 3
82 is even.
83 is odd
84 is even.
85 is odd and it is divisible by 5
86 is even.
87 is odd and it is divisible by 3
88 is even.
89 is odd
90 is even.
91 is odd and it is divisible by 7
92 is even.
93 is odd and it is divisible by 3
94 is even.
95 is odd and it is divisible by 5
96 is even.
97 is odd
98 is even.
99 is odd and it is divisible by 3
100 is even.

4.15.Counter Controlled Repetition

4.15.1.Using the While structure to demonstrate counter-controlled repetition.

Module Tester

    Sub Main()
        Dim counter As Integer = 2

      While counter <= 10 
         Console.Write(counter & " ")
         counter += 2 
      End While

    End Sub 

End Module

 
2 4 6 8 10

4.15.2.Using the For/Next structure to demonstrate counter-controlled repetition.

Module Tester

    Sub Main()
        Dim counter As Integer

      For counter = 2 To 10 Step 2
         Console.Write(counter & " ")
      Next

    End Sub 

End Module

 
2 4 6 8 10

4.16.GoTo

4.16.1.GoTo statement with Label

Option Strict On
 Imports System
 Module Module1

    Sub Main( )
       Dim counterVariable As Integer = 0

       repeat:  
       Console.WriteLine("counterVariable: {0}", counterVariable)

       counterVariable += 1
       If counterVariable < 10 Then
          GoTo repeat 
       End If
    End Sub 

 End Module

 
counterVariable: 0
counterVariable: 1
counterVariable: 2
counterVariable: 3
counterVariable: 4
counterVariable: 5
counterVariable: 6
counterVariable: 7
counterVariable: 8
counterVariable: 9

4.17.Imports

4.17.1.Imports System

Module MyModule

  Enum Medal As Short
    Gold
    Silver
    Bronze
  End Enum

  Sub Main()
    Dim myMedal As Medal = Medal.Bronze
    Console.WriteLine("My medal: " & myMedal.ToString)
End Sub

End Module

 
My medal: Bronze

4.17.2.Imports command

Imports System

Public Class Step2
    Shared Sub Main()
        Console.WriteLine("info")
    End Sub
End Class

 
info

4.18.On Error GoTo

4.18.1.On Error GoTo errorhandle

Imports System.IO

public class Tester
   public Shared Sub Main

        Dim myfile As System.IO.File
        Dim w As System.IO.StreamWriter
        On Error GoTo errorhandle

        w = myfile.AppendText("a:\temp.txt")
        w.Write("a")
        w.Close()
        Exit Sub

        errorhandle:
        Console.WriteLine("Please Insert")
        Exit Sub
        Resume
   End Sub
   
End class

 
Please Insert

4.18.2.Select Case Err.Number

Imports System.IO

public class Tester
   public Shared Sub Main

        On Error GoTo ErrorHandle
        Exit Sub

        ErrorHandle:
        Select Case Err.Number
            Case 52
                Console.WriteLine("File Name Exception")
            Case 53
                Console.WriteLine("File cannot be found")
            Case 54
                Console.WriteLine("File Mode Exception")
            Case 55
                Console.WriteLine("File is aleady open")
            Case 58
                Console.WriteLine("File exists")
            Case 68
                Console.WriteLine("Device is not available")
            Case 75
                Console.WriteLine("Path Exception")
            Case 76
                Console.WriteLine("Path cannot be found")
            Case Else
                Console.WriteLine("Other")
        End Select

   End Sub
   
End class

 
4.19.Resume

4.19.1.Resume

Module Module1
    Sub Main()
        On Error GoTo Handler
        Dim i1 As Integer = 0
        Dim i2 As Integer = 128
        Dim intResult As Integer
        intResult = i2 / i1
        Console.WriteLine("Press Enter to continue...")
        Console.ReadLine()
        Exit Sub
Handler:
        Console.WriteLine("An overflow error occurred.")
        Resume Next
    End Sub
End Module

 
An overflow error occurred.
Press Enter to continue..
4.20.Using statement

4.20.1.Using statement

public class Test
   public Shared Sub Main
        Using _
          emp1 As New Employee("Ann", "Archer"), _
          emp2 As New Employee("Bob", "Beagle")
            Dim i As Integer
        End Using


   End Sub
End class


Public Class Employee
    Implements IDisposable

    Public Sub New(ByVal first_name As String, ByVal last_name As String)

    End Sub

    Private disposedValue As Boolean = False

    Protected Overridable Sub Dispose(ByVal disposing As Boolean)
        If Not Me.disposedValue Then
            If disposing Then
                Console.WriteLine("TODO: free unmanaged resources when explicitly called")
            End If

            Console.WriteLine("TODO: free shared unmanaged resources")
        End If
        Me.disposedValue = True
    End Sub

    Public Sub Dispose() Implements IDisposable.Dispose
        Dispose(True)
        GC.SuppressFinalize(Me)
    End Sub

    Protected Overrides Sub Finalize()
        Dispose(False)
        MyBase.Finalize()
    End Sub
End Class

 
TODO: free unmanaged resources when explicitly called
TODO: free shared unmanaged resources
TODO: free unmanaged resources when explicitly called
TODO: free shared unmanaged resources

Wyszukiwarka

Podobne podstrony:
kurs vba Statements 4 kolumny
EXCEL 2003 Kurs VBA
kurs vba Language Basics 1 kolumny
kurs vba Data Type 2 kolumny
kurs vba Operator 3 kolumny
kurs vba Date Time 5 kolumny
kurs vba Data Type 2
kurs vba Date Time 5
kurs vba Operator 3
KURS ETYKI
Choroba hemolityczna p odu na kurs
zapotrzebowanie ustroju na skladniki odzywcze 12 01 2009 kurs dla pielegniarek (2)
kurs
wady postawy kurs
ostre białaczki 24 11 2008 (kurs)

więcej podobnych podstron