System.Convert.ToString 方法 (String, IFormatProvider)

System.Convert.ToString 方法 (String, IFormatProvider)例子

该方法返回未修改的 String 而不引用 IFormatProvider 对象。

// 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

*/

相关资源

Convert 类

ToString 重载

System 命名空间

MSDN