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Convert.ToString Method (Object)

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

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public static string ToString (
	Object value
)
public static String ToString (
	Object value
)
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).

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

The following code example converts a non-numeric Object and a boxed numeric value to String s with the ToString method, using default formatting.

// 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

*/ 

// Example of Convert.ToString( non-numeric types, IFormatProvider ).
import System.* ;
import 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 Object GetFormat(Type argType) 
    {
        // Here, the type of argType is displayed, and GetFormat
        // always returns Nothing.
        Console.Write("{0,-40}", argType.ToString());
        return null ;
    } //GetFormat
} //DummyProvider

class ConvertNonNumericProviderDemo
{   
    public static void main(String[] args)
    {  
        // 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 = (System.Double)(-98765.4321);
        DateTime dayTimeA =  new DateTime(2001, 9, 11, 13, 45, 0);
      
        boolean 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);
    } //main
} //ConvertNonNumericProviderDemo

/*
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@33c0d9d

*/

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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