VB.NET Convert.ToString方法代碼示例

Dim bases() As Integer = { 2, 8, 10, 16}
Dim numbers() As Short = { Int16.MinValue, -13621, -18, 12, 19142, _
                           Int16.MaxValue }

For Each base As Integer In bases
   Console.WriteLine("Base {0} conversion:", base)
   For Each number As Short In numbers
      Console.WriteLine("   {0,-8}  -->  0x{1}", _
                        number, Convert.ToString(number, base))
   Next
Next

Dim numbers() As Short = { Int16.MinValue, Int16.MaxValue}
Dim nfi As New System.Globalization.NumberFormatInfo()
nfi.NegativeSign = "~"
nfi.PositiveSign = "!"

For Each number As Short In numbers
   Console.WriteLine("{0,-8}  -->  {1,8}", _
                     Convert.ToString(number, System.Globalization.CultureInfo.InvariantCulture), _
                     Convert.ToString(number, nfi))
Next

Dim number As ULong = UInt64.MaxValue
Dim nfi As New System.Globalization.NumberFormatInfo()
nfi.NegativeSign = "~"
nfi.PositiveSign = "!"

Console.WriteLine("{0,-12}  -->  {1,12}", _
                  Convert.ToString(number, System.Globalization.CultureInfo.InvariantCulture), _
                  Convert.ToString(number, nfi))

' Define an array of numbers to display.
Dim numbers() As Decimal = { 1734231911290.16d, -17394.32921d, _
                             3193.23d, 98012368321.684d }
' Define the culture names used to display them.
Dim cultureNames() As String = { "en-US", "fr-FR", "ja-JP", "ru-RU" }

For Each number As Decimal In numbers
   Console.WriteLine("{0}:", Convert.ToString(number, _
                             System.Globalization.CultureInfo.InvariantCulture))
   For Each cultureName As String In cultureNames
      Dim culture As New System.Globalization.CultureInfo(cultureName)
      Console.WriteLine("   {0}: {1,20}", _
                        culture.Name, Convert.ToString(number, culture))
   Next
   Console.WriteLine()
Next

' Specify the date to be formatted using various cultures.
Dim tDate As New Date(2010, 4, 15, 20, 30, 40, 333)
' Specify the cultures.
Dim cultureNames() As String = { "en-US", "es-AR", "fr-FR", "hi-IN", _
                                 "ja-JP", "nl-NL", "ru-RU", "ur-PK" }

Console.WriteLine("Converting the date {0}: ", _
                  Convert.ToString(tDate, _
                          System.Globalization.CultureInfo.InvariantCulture))

For Each cultureName As String In CultureNames
   Dim culture As New System.Globalization.CultureInfo(cultureName)
   Dim dateString As String = Convert.ToString(tDate, culture)
   Console.WriteLine("   {0}:  {1,-12}", _
                     culture.Name, dateString)
Next

Dim numbers() As Integer = { Int32.MinValue, Int32.MaxValue}
Dim nfi As New System.Globalization.NumberFormatInfo()
nfi.NegativeSign = "~"
nfi.PositiveSign = "!"

For Each number As Integer In numbers
   Console.WriteLine("{0,-12}  -->  {1,12}", _
                     Convert.ToString(number, System.Globalization.CultureInfo.InvariantCulture), _
                     Convert.ToString(number, nfi))
Next

' Define an array of numbers to display.
Dim numbers() As Double = { -1.5345e16, -123.4321, 19092.123, _
                            1.1734231911290e16 }
' Define the culture names used to display them.
Dim cultureNames() As String = { "en-US", "fr-FR", "ja-JP", "ru-RU" }

For Each number As Double In numbers
   Console.WriteLine("{0}:", Convert.ToString(number, _
                             System.Globalization.CultureInfo.InvariantCulture))
   For Each cultureName As String In cultureNames
      Dim culture As New System.Globalization.CultureInfo(cultureName)
      Console.WriteLine("   {0}: {1,20}", _
                        culture.Name, Convert.ToString(number, culture))
   Next
   Console.WriteLine()
Next

Dim bases() As Integer = { 2, 8, 10, 16}
Dim numbers() As Integer = { Int32.MinValue, -19327543, -13621, -18, 12, _
                             19142, Int32.MaxValue }

For Each base As Integer In bases
   Console.WriteLine("Base {0} conversion:", base)
   For Each number As Integer In numbers
      Console.WriteLine("   {0,-15}  -->  0x{1}", _
                        number, Convert.ToString(number, base))
   Next
Next

Dim numbers() As SByte = { SByte.MinValue, -12, 17, SByte.MaxValue}
Dim nfi As New System.Globalization.NumberFormatInfo()
nfi.NegativeSign = "~"
nfi.PositiveSign = "!"
For Each number As SByte In numbers
   Console.WriteLine(Convert.ToString(number, nfi))
Next

Dim bases() As Integer = { 2, 8, 10, 16}
Dim numbers() As Long = { Int64.MinValue, -193275430, -13621, -18, 12, _
                             1914206117, Int64.MaxValue }

For Each base As Integer In bases
   Console.WriteLine("Base {0} conversion:", base)
   For Each number As Long In numbers
      Console.WriteLine("   {0,-23}  -->  0x{1}", _
                        number, Convert.ToString(number, base))
   Next
Next

Public Class Temperature 
   Private m_Temp As Decimal

   Public Sub New(temperature As Decimal)
      Me.m_Temp = temperature
   End Sub
   
   Public ReadOnly Property Celsius() As Decimal
      Get
         Return Me.m_Temp
      End Get   
   End Property
   
   Public ReadOnly Property Kelvin() As Decimal
      Get
         Return Me.m_Temp + 273.15d   
      End Get
   End Property
   
   Public ReadOnly Property Fahrenheit() As Decimal
      Get
         Return Math.Round(CDec(Me.m_Temp * 9 / 5 + 32), 2)
      End Get      
   End Property
   
   Public Overrides Function ToString() As String
      Return m_Temp.ToString("N2") & " °C"
   End Function
End Class

Module Example
   Public Sub Main()
      Dim cold As New Temperature(-40)
      Dim freezing As New Temperature(0)
      Dim boiling As New Temperature(100)
      
      Console.WriteLine(Convert.ToString(cold, Nothing))
      Console.WriteLine(Convert.ToString(freezing, Nothing))
      Console.WriteLine(Convert.ToString(boiling, Nothing))
   End Sub
End Module

Public Class Temperature : Implements IFormattable 
   Private m_Temp As Decimal 

   Public Sub New(temperature As Decimal)
      Me.m_Temp = temperature
   End Sub 

   Public ReadOnly Property Celsius As Decimal 
      Get 
         Return Me.m_Temp
      End Get    
   End Property 

   Public ReadOnly Property Kelvin As Decimal 
      Get 
         Return Me.m_Temp + 273.15d   
      End Get 
   End Property 

   Public ReadOnly Property Fahrenheit As Decimal 
      Get 
         Return Math.Round(CDec(Me.m_Temp * 9 / 5 + 32), 2)
      End Get       
   End Property 

   Public Overrides Function ToString() As String 
      Return ToString("G", Nothing) 
   End Function 
   
   Public Overloads Function ToString(fmt As String, 
                                      provider As IFormatProvider) As String _
                             Implements IFormattable.ToString
      Dim formatter As TemperatureProvider = Nothing
      If provider IsNot Nothing Then formatter = TryCast(provider.GetFormat(GetType(TemperatureProvider)),
                                                         TemperatureProvider)

      If String.IsNullOrWhiteSpace(fmt) Then
         If formatter IsNot Nothing Then
            fmt = formatter.Format
         Else
            fmt = "G"
         End If
      End If

      Select Case fmt.ToUpper()
         Case "G", "C"
            Return m_Temp.ToString("N2") & " °C" 
         Case "F"
            Return Fahrenheit.ToString("N2") + " °F"
         Case "K"
            Return Kelvin.ToString("N2") + " K"
         Case Else
            Throw New FormatException(String.Format("'{0}' is not a valid format specifier.", fmt))
      End Select
   End Function                             
End Class 

Public Class TemperatureProvider : Implements IFormatProvider
   Private fmtStrings() As String = { "C", "G", "F", "K" }
   Private rnd As New Random()
   
   Public Function GetFormat(formatType As Type) As Object _
                   Implements IFormatProvider.GetFormat 
      Return Me 
   End Function
   
   Public ReadOnly Property Format As String
      Get
         Return fmtStrings(rnd.Next(0, fmtStrings.Length))
      End Get
   End Property
End Class

Module Example
   Public Sub Main()
      Dim cold As New Temperature(-40)
      Dim freezing As New Temperature(0)
      Dim boiling As New Temperature(100)

      Dim tp As New TemperatureProvider()
      
      Console.WriteLine(Convert.ToString(cold, tp))
      Console.WriteLine(Convert.ToString(freezing, tp))
      Console.WriteLine(Convert.ToString(boiling, tp))
   End Sub 
End Module

' Define an array of numbers to display.
Dim numbers() As Single = { -1.5345e16, -123.4321, 19092.123, _
                            1.1734231911290e16 }
' Define the culture names used to display them.
Dim cultureNames() As String = { "en-US", "fr-FR", "ja-JP", "ru-RU" }

For Each number As Single In numbers
   Console.WriteLine("{0}:", Convert.ToString(number, _
                             System.Globalization.CultureInfo.InvariantCulture))
   For Each cultureName As String In cultureNames
      Dim culture As New System.Globalization.CultureInfo(cultureName)
      Console.WriteLine("   {0}: {1,20}", _
                        culture.Name, Convert.ToString(number, culture))
   Next
   Console.WriteLine()
Next

' Example of Convert.ToString( non-numeric types, IFormatProvider ).
Imports System.Globalization

' An instance of this class can be passed to methods that require 
' an IFormatProvider.
Public Class DummyProvider
    Implements IFormatProvider

    ' Normally, GetFormat returns an object of the requested type
    ' (usually itself) if it is able; otherwise, it returns Nothing. 
    Public Function GetFormat( argType As Type ) As Object _
        Implements IFormatProvider.GetFormat

        ' Here, the type of argType is displayed, and GetFormat
        ' always returns Nothing.
        Console.Write( "{0,-40}", argType.ToString( ) )
        Return Nothing

    End Function 
End Class

Module ConvertNonNumericProviderDemo

    Sub Main( )

        ' Create an instance of the IFormatProvider.
        Dim provider    As New DummyProvider( )
        Dim converted   As String

        ' Convert these values using DummyProvider.
        Dim Int32A      As Integer  = -252645135   
        Dim DoubleA     As Double   = 61680.3855
        Dim ObjDouble   As Object   = CType( -98765.4321, Object )
        Dim DayTimeA    As DateTime = _
                            new DateTime( 2001, 9, 11, 13, 45, 0 )

        Dim BoolA       As Boolean  = True
        Dim StringA     As String   = "Qwerty"
        Dim CharA       As Char     = "$"c
        Dim TSpanA      As TimeSpan = New TimeSpan( 0, 18, 0 )
        Dim ObjOther    As Object   = CType( provider, Object )

        Console.WriteLine( "This example of " & _
            "Convert.ToString( non-numeric, IFormatProvider ) " & _
            vbCrLf & "generates the following output. The " & _
            "provider type, argument type, " & vbCrLf & "and " & _
            "argument value are displayed." )
        Console.WriteLine( vbCrLf & _
            "Note: The IFormatProvider object is not called for " & _
            "Boolean, String, " & vbCrLf & "Char, TimeSpan, " & _
            "and non-numeric Object." )

        ' The format provider is called for these conversions.
        Console.WriteLine( )
        converted =  Convert.ToString( Int32A, provider )
        Console.WriteLine( "Int32    {0}", converted )
        converted =  Convert.ToString( DoubleA, provider )
        Console.WriteLine( "Double   {0}", converted )
        converted =  Convert.ToString( ObjDouble, provider )
        Console.WriteLine( "Object   {0}", converted )
        converted =  Convert.ToString( DayTimeA, provider )
        Console.WriteLine( "DateTime {0}", converted )

        ' The format provider is not called for these conversions.
        Console.WriteLine( )
        converted =  Convert.ToString( BoolA, provider )
        Console.WriteLine( "Boolean  {0}", converted )
        converted =  Convert.ToString( StringA, provider )
        Console.WriteLine( "String   {0}", converted )
        converted =  Convert.ToString( CharA, provider )
        Console.WriteLine( "Char     {0}", converted )
        converted =  Convert.ToString( TSpanA, provider )
        Console.WriteLine( "TimeSpan {0}", converted )
        converted =  Convert.ToString( ObjOther, provider )
        Console.WriteLine( "Object   {0}", converted )

    End Sub
End Module

' This example of Convert.ToString( non-numeric, IFormatProvider )
' generates the following output. The provider type, argument type,
' and argument value are displayed.
'
' Note: The IFormatProvider object is not called for Boolean, String,
' Char, TimeSpan, and non-numeric Object.
' 
' System.Globalization.NumberFormatInfo   Int32    -252645135
' System.Globalization.NumberFormatInfo   Double   61680.3855
' System.Globalization.NumberFormatInfo   Object   -98765.4321
' System.Globalization.DateTimeFormatInfo DateTime 9/11/2001 1:45:00 PM
' 
' Boolean  True
' String   Qwerty
' Char     $
' TimeSpan 00:18:00
' Object   DummyProvider

Dim number As UShort = UInt16.MaxValue
Dim nfi As New System.Globalization.NumberFormatInfo()
nfi.NegativeSign = "~"
nfi.PositiveSign = "!"

Console.WriteLine("{0,-6}  -->  {1,6}", _
                  Convert.ToString(number, System.Globalization.CultureInfo.InvariantCulture), _
                  Convert.ToString(number, nfi))