ICustomFormatter IFormatProvider : ICustomFormatter : Class C# Examples

    
/*
Quote  from
Accelerated  C#  2005
#  By  Trey  Nash
#  ISBN:  1-59059-717-6
#  432  pp.
#  Published:  Aug  2006
*/

using  System;
using  System.Text;
using  System.Globalization;

public  class  ComplexDbgFormatter  :  ICustomFormatter,  IFormatProvider
{
        public  object  GetFormat(  Type  formatType  )  {
                if(  formatType  ==  typeof(ICustomFormatter)  )  {
                        return  this;
                }  else  {
                        return  CultureInfo.CurrentCulture.
                                GetFormat(  formatType  );
                }
        }

        public  string  Format(  string  format,  object  arg,  IFormatProvider  formatProvider  )  {
                if(  arg.GetType()  ==  typeof(Complex)  &&  format  ==  "DBG"  )  {
                        Complex  cpx  =  (Complex)  arg;

                        StringBuilder  sb  =  new  StringBuilder();
                        sb.Append(  arg.GetType().ToString()  +  "  "  );
                        sb.AppendFormat(  "Real:{0}  ",  cpx.Real  );
                        sb.AppendFormat(  "Img:  {0}  ",  cpx.Img  );
                        return  sb.ToString();
                }  else  {
                        IFormattable  formatable  =  arg  as  IFormattable;
                        if(  formatable  !=  null  )  {
                                return  formatable.ToString(  format,  formatProvider  );
                        }  else  {
                                return  arg.ToString();
                        }
                }
        }
}

public  struct  Complex  :  IFormattable
{
        public  Complex(  double  Real,  double  Img  )  {
                this.Real  =  Real;
                this.Img  =  Img;
        }

        public  string  ToString(  string  format,  IFormatProvider  formatProvider  )  {
                StringBuilder  sb  =  new  StringBuilder();
                sb.Append(  "(  "  +  Real.ToString(format,  formatProvider)  );
                sb.Append(  "  :  "  +  Img.ToString(format,  formatProvider)  );
                sb.Append(  "  )"  );

                return  sb.ToString();
        }

        public  double  Real;
        public  double  Img;
}

public  class  MainClass
{
        static  void  Main()  {
                CultureInfo  local  =  CultureInfo.CurrentCulture;
                CultureInfo  germany  =  new  CultureInfo(  "de-DE"  );

                Complex  cpx  =  new  Complex(  12.3456,  1234.56  );

                string  strCpx  =  cpx.ToString(  "F",  local  );
                Console.WriteLine(  strCpx  );

                strCpx  =  cpx.ToString(  "F",  germany  );
                Console.WriteLine(  strCpx  );

                ComplexDbgFormatter  dbgFormatter  =  new  ComplexDbgFormatter();
                strCpx  =  String.Format(  dbgFormatter,"{0:DBG}",    cpx  );
                Console.WriteLine(  "\nDebugging  output:\n{0}",  strCpx  );
        }
}