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Convert.ToString Method (Object)

.NET Framework 1.1

Converts the value of the specified Object to its String representation.

[Visual Basic]
Overloads Public Shared Function ToString( _
   ByVal value As Object _
) As String
[C#]
public static string ToString(
 object value
);
[C++]
public: static String* ToString(
 Object* value
);
[JScript]
public static function ToString(
   value : Object
) : String;

Parameters

value: An Object or a null reference (Nothing in Visual Basic).

Return Value

The String representation of the value of value, or String.Empty if value is a null reference (Nothing in Visual Basic).

Remarks

The return value is the result of invoking the ToString method of the underlying type of value.

Example

[Visual Basic, C#, C++] The following code example converts a non-numeric Object and a boxed numeric value to String s with the ToString method, using default formatting.

[Visual Basic] 
' 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

[C#] 
// Example of Convert.ToString( non-numeric types, IFormatProvider ).
using System;
using System.Globalization;

// An instance of this class can be passed to methods that require 
// an IFormatProvider.
public class DummyProvider : IFormatProvider
{
    // Normally, GetFormat returns an object of the requested type
    // (usually itself) if it is able; otherwise, it returns Nothing. 
    public object GetFormat( Type argType )
    {
        // Here, the type of argType is displayed, and GetFormat
        // always returns Nothing.
        Console.Write( "{0,-40}", argType.ToString( ) );
        return null;
    }
}

class ConvertNonNumericProviderDemo
{
    static void Main( )
    {
        // Create an instance of the IFormatProvider.
        DummyProvider provider = new DummyProvider( );
        string converted;

        // Convert these values using DummyProvider.
        int      Int32A     = -252645135;
        double   DoubleA    = 61680.3855;
        object   ObjDouble  = (object)( -98765.4321 );
        DateTime DayTimeA   = new DateTime( 2001, 9, 11, 13, 45, 0 );

        bool     BoolA      = true;
        string   StringA    = "Qwerty";
        char     CharA      = '$';
        TimeSpan TSpanA     = new TimeSpan( 0, 18, 0 );
        object   ObjOther   = (object)provider;

        Console.WriteLine( "This example of " +
            "Convert.ToString( non-numeric, IFormatProvider ) \n" +
            "generates the following output. The provider type, " +
            "argument type, \nand argument value are displayed." );
        Console.WriteLine( "\nNote: The IFormatProvider object is " +
            "not called for Boolean, String, \nChar, TimeSpan, " +
            "and non-numeric Object." );

        // The format provider is called for these conversions.
        Console.WriteLine( );
        converted = Convert.ToString( Int32A, provider );
        Console.WriteLine( "int      {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( "bool     {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 );
    }
}

/*
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   int      -252645135
System.Globalization.NumberFormatInfo   double   61680.3855
System.Globalization.NumberFormatInfo   object   -98765.4321
System.Globalization.DateTimeFormatInfo DateTime 9/11/2001 1:45:00 PM

bool     True
string   Qwerty
char     $
TimeSpan 00:18:00
object   DummyProvider

*/ 

[C++] 
// Example of Convert::ToString( non-numeric types, IFormatProvider ).
#using <mscorlib.dll>
using namespace System;
using namespace System::Globalization;

#define null (Object*)0

// An instance of this class can be passed to methods that require 
// an IFormatProvider.
__gc class DummyProvider : public IFormatProvider
{
    // Normally, GetFormat returns an object of the requested type
    // (usually itself) if it is able; otherwise, it returns Nothing. 
    public: Object* GetFormat( Type* argType )
    {
        // Here, the type of argType is displayed, and GetFormat
        // always returns Nothing.
        Console::Write( S"{0,-40}", argType->ToString( ) );
        return null;
    }
};

void main( )
{
    // Create an instance of the IFormatProvider.
    DummyProvider*  provider = new DummyProvider( );
    String*         converted;

    // Convert these values using DummyProvider.
    int         Int32A     = -252645135;
    double      DoubleA    = 61680.3855;
    Object*     ObjDouble  = __box( -98765.4321 );
    DateTime    DayTimeA   = DateTime( 2001, 9, 11, 13, 45, 0 );

    bool        BoolA      = true;
    String*     StringA    = S"Qwerty";
    Char        CharA      = '$';
    TimeSpan    TSpanA     = TimeSpan( 0, 18, 0 );
    Object*     ObjOther   = static_cast<Object*>( provider );

    Console::WriteLine( S"This example of " 
        S"Convert::ToString( non-numeric, IFormatProvider* ) \n" 
        S"generates the following output. The provider type, " 
        S"argument type, \nand argument value are displayed." );
    Console::WriteLine( S"\nNote: The IFormatProvider object is " 
        S"not called for Boolean, String, \nChar, TimeSpan, " 
        S"and non-numeric Object." );

    // The format provider is called for these conversions.
    Console::WriteLine( );
    converted = Convert::ToString( Int32A, provider );
    Console::WriteLine( S"int      {0}", converted );
    converted = Convert::ToString( DoubleA, provider );
    Console::WriteLine( S"double   {0}", converted );
    converted = Convert::ToString( ObjDouble, provider );
    Console::WriteLine( S"Object   {0}", converted );
    converted = Convert::ToString( DayTimeA, provider );
    Console::WriteLine( S"DateTime {0}", converted );

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

/*
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   int      -252645135
System.Globalization.NumberFormatInfo   double   61680.3855
System.Globalization.NumberFormatInfo   Object   -98765.4321
System.Globalization.DateTimeFormatInfo DateTime 9/11/2001 1:45:00 PM

bool     True
String   Qwerty
Char     $
TimeSpan 00:18:00
Object   DummyProvider
*/

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button in the upper-left corner of the page.

Requirements