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Convert.ToString Method (String, IFormatProvider)

Returns the specified string instance; no actual conversion is performed.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
'Declaration
Public Shared Function ToString ( _
	value As String, _
	provider As IFormatProvider _
) As String

Parameters

value
Type: System.String

The string to return.

provider
Type: System.IFormatProvider

An object that supplies culture-specific formatting information. This parameter is ignored.

Return Value

Type: System.String
value is returned unchanged.

The following example calls the ToString method with a String parameter. The method returns the unmodified String without referencing the IFormatProvider object.

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

' 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

.NET Framework

Supported in: 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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