IFormattable,ICustomFormatter, IFormatProvider接口

代码    class  Point : IFormattable    {         public   int  x, y;         public  Point( int  x,  int  y)        {             this .x  =  x;             this .y  =  y;        }         public   override  String ToString() {  return  ToString( null ,  null ); }         public  String ToString(String format, IFormatProvider fp)        {             if  (format  ==   null )  return  String.Format( " ({0}, {1}) " , x, y);             if  (format  ==   " x " )  return  x.ToString();             if  (format  ==   " y " )  return  y.ToString();             throw   new  FormatException(String.Format( " Invalid format string: '{0}'. " , format));        }    }     public   sealed   class  App    {         static   void  Main()        {            Point p  =   new  Point( 5 ,  98 );            Console.WriteLine( " This is my point:  "   +  p.ToString());            Console.WriteLine( " The point's x value is {0:x} " , p);            Console.WriteLine( " The point's y value is {0:y} " , p);             try             {                Console.WriteLine( " Invalid way to format a point: {0:x+y} " , p);            }             catch  (FormatException e)            {                Console.WriteLine( " The last line could not be displayed: {0} " , e.Message);            }            Console.WriteLine( " yrst {0:C} " , 11 );            Console.Read();        }    }

 

 

 

代码    public   class  MyClass : System.IFormattable    {        Double d;         public  MyClass(Double d)        {             this .d  =  d;        }         public   string  ToString( string  format, IFormatProvider formatProvider)        {             return  (format  ==   " MyFormat " )  ?   " *** "   +  d.ToString(formatProvider) : d.ToString(format, formatProvider);        }    }      class  Program    {         static   void  Main( string [] args)        {            System.Globalization.CultureInfo culture  =   null ;            MyClass myClass  =   new  MyClass( 5 );             // 当IFormatProvider为空时,调用的是当前线程关联的文化信息              Console.WriteLine( " 显示中国货币格式:{0} " , myClass.ToString( " C " ,  null ));            culture  =  System.Globalization.CultureInfo.CurrentCulture;            Console.WriteLine( " 显示当前系统默认货币格式:{0} " , myClass.ToString( " C " , culture));            culture  =   new  System.Globalization.CultureInfo( " zh-HK " );            Console.WriteLine( " 显示香港特别行政区货币格式:{0} " , myClass.ToString( " C " , culture));            Console.WriteLine( " 显示我自己定义的货币格式:{0} " , myClass.ToString( " MyFormat " ,  null ));            Console.ReadLine();         }    }

 

 

 

 

 

代码    public   class  MyBaseFormat : System.ICustomFormatter, System.IFormatProvider    {         // 如果format Type与当前实例类型相同，则为当前实例，否则为空引用           public   object  GetFormat(Type format)        {             if  (format  ==   typeof (ICustomFormatter))                 return   this ;             return   null ;        }         // 实现Format方法说明:          // 如果您的格式方法不支持格式，则确定正在设置格式的对象是否实现 IFormattable 接口。          // 如果实现，请调用该接口的IFormattable.ToString 方法。          // 否则，调用基础对象的默认 Object.ToString 方法。           public   string  Format( string  format,  object  arg, IFormatProvider provider)        {             if  (format  ==   null )            {                 if  (arg  is  IFormattable)                     return  ((IFormattable)arg).ToString(format, provider);                 return  arg.ToString();            }             else             {                 if  (format  ==   " MyBaseFormat " )                {                     return   " *** "   +  arg.ToString();                }                 else                 {                     if  (arg  is  IFormattable)                         return  ((IFormattable)arg).ToString(format, provider);                     return  arg.ToString();                }            }        }    }      class  Program    {         static   void  Main( string [] args)        {             string  printString  =  String.Empty;             int  i  =   100 ;            MyBaseFormat myBaseFormat  =   new  MyBaseFormat();            printString  =   string .Format(myBaseFormat,  " 显示正常格式:{0} " , i);            Console.WriteLine(printString);            printString  =   string .Format(myBaseFormat,  " 显示正常格式:{0:C} " , i);            Console.WriteLine(printString);            printString  =   string .Format(myBaseFormat,  " 显示自定义格式{0:MyBaseFormat} " , i);            Console.WriteLine(printString);            Console.ReadLine();         }    }

 

 

转载于:https://www.cnblogs.com/renjuwht/archive/2010/01/02/1638081.html

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