The formatting routines account for a considerable part of the SysUtils unit. Some of them are nested and consist in about 1000 lines of code. Nevertheless the translated code works nearly perfect. Examples to the formatting routines from

Delphi Basics Format

were modified slightly to be able to use them for test purposes. The code translated with Delphi2C# compiles and works without additional manual processing without faults.

using static dbsc_format.dbsc_formatInterface;
using static dbsc_format.dbsc_formatImplementation;
using System;
using static System.SystemInterface;
using System.SysUtils;
using static System.SysUtils.SysUtilsInterface;

namespace dbsc_format
{

public class dbsc_formatInterface
{
//http://www.delphibasics.co.uk/RTL.asp?Name=Format
//http://www.delphibasics.co.uk/RTL.asp?Name=FloatToStr
//http://www.delphibasics.co.uk/RTL.asp?Name=FormatFloat
public static bool FormatTest()
{
  bool result = false;
  result = true;
  result = result && FormatTest1();
  result = result && FormatTest2();
  result = result && FloatToStrTest1();
  result = result && FormatFloatTest1();
  return result;
}

} // class dbsc_formatInterface

public class dbsc_formatImplementation
{

public static bool FormatTest1()
{
  bool result = false;
  result = true;
  // Just 1 data item
  result = result && (Format("%s", new object[]{"Hello"}) == "Hello");

  // A mix of literal text and a data item
  result = result && (Format("String = %s", new object[]{"Hello"}) == "String = Hello");
   //ShowMessage('');

  // Examples of each of the data types
  result = result && (Format("Decimal          = %d", new object[]{-123}) == "Decimal          = -123");
  result = result && (Format("Exponent         = %e", new object[]{12345.678D}) == "Exponent         = 1,23456780000000E+004");
  result = result && (Format("Fixed            = %f", new object[]{12345.678D}) == "Fixed            = 12345,68");
  result = result && (Format("General          = %g", new object[]{12345.678D}) == "General          = 12345,678");
  result = result && (Format("Number           = %n", new object[]{12345.678D}) == "Number           = 12.345,68");
  result = result && (Format("Money            = %m", new object[]{12345.678D}) == "Money            = 12.345,68 €");
   // makes no sense under C#
   // result := result and (Format('Pointer          = %p', [addr(text)]) = 'Pointer          = 0069FC90');
  result = result && (Format("String           = %s", new object[]{"Hello"}) == "String           = Hello");
  result = result && (Format("Unsigned decimal = %u", new object[]{123}) == "Unsigned decimal = 123");
  result = result && (Format("Hexadecimal      = %x", new object[]{140}) == "Hexadecimal      = 8C");
  return result;
}

public static bool FormatTest2()
{
  bool result = false;
  result = true;
  // The width value dictates the output size
  // with blank padding to the left
  // Note the <> characters are added to show formatting
  result = result && (Format("Padded decimal    = <%7d>", new object[]{1234}) == "Padded decimal    = <   1234>");

  // With the '-' operator, the data is left justified
  result = result && (Format("Justified decimal = <%-7d>", new object[]{1234}) == "Justified decimal = <1234   >");

  // The precision value forces 0 padding to the desired size
  result = result && (Format("0 padded decimal  = <%.6d>", new object[]{1234}) == "0 padded decimal  = <001234>");

  // A combination of width and precision
  // Note that width value precedes the precision value
  result = result && (Format("Width + precision = <%8.6d>", new object[]{1234}) == "Width + precision = <  001234>");

  // The index value allows the next value in the data array
  // to be changed
  result = result && (Format("Reposition after 3 strings = %s %s %s %1:s %s", new object[]{"Zero", "One", "Two", "Three"}) == "Reposition after 3 strings = Zero One Two One Two");

  // One or more of the values may be provided by the
  // data array itself. Note that testing has shown that an *
  // for the width parameter can yield EConvertError.
  result = result && (Format("In line           = <%10.4d>", new object[]{1234}) == "In line           = <      1234>");
  result = result && (Format("Part data driven  = <%*.4d>", new object[]{10, 1234}) == "Part data driven  = <      1234>");
  result = result && (Format("Data driven       = <%*.*d>", new object[]{10, 4, 1234}) == "Data driven       = <      1234>");
  return result;
}

public static bool FloatToStrTest1()
{
  bool result = false;
  double amount1 = 0.0D;
  double amount2 = 0.0D;
  double amount3 = 0.0D;
  result = true;
  amount1 = 1234567890.123456789D;  // High precision number
  amount2 = 1234567890123456.123D;  // High mantissa digits
  amount3 = 1E100D;                 // High value number
  result = result && (FloatToStr(amount1) == "1234567890,12346");
  result = result && (FloatToStr(amount2) == "1,23456789012346E15");
  result = result && (FloatToStr(amount3) == "1E100");
  return result;
}

public static bool FormatFloatTest1()
{
  bool result = false;
  double flt = 0.0D;
  result = true;
  // Set up our floating point number
  flt = 1234.567D;

  // Display a sample value using all of the format options

  // Round out the decimal value
  result = result && (FormatFloat("#####", flt) == "1235");
  result = result && (FormatFloat("00000", flt) == "01235");
  result = result && (FormatFloat("0", flt) == "1235");
  result = result && (FormatFloat("#,##0", flt) == "1.235");
  result = result && (FormatFloat(",0", flt) == "1.235");

  // Include the decimal value
  result = result && (FormatFloat("0.####", flt) == "1234,567");
  result = result && (FormatFloat("0.0000", flt) == "1234,5670");

  // Scientific format
  result = result && (FormatFloat("0.0000000E+00", flt) == "1,2345670E+03");
  result = result && (FormatFloat("0.0000000E-00", flt) == "1,2345670E03");
  result = result && (FormatFloat("#.#######E-##", flt) == "1,234567E3");

  // Include freeform text
  result = result && (FormatFloat("\"Value = \"0.0", flt) == "Value = 1234,6");

  // Different formatting for negative numbers
  result = result && (FormatFloat("0.0", -1234.567D) == "-1234,6");
  result = result && (FormatFloat("0.0 \"CR\";0.0 \"DB\"", -1234.567D) == "1234,6 DB");
  result = result && (FormatFloat("0.0 \"CR\";0.0 \"DB\"", 1234.567D) == "1234,6 CR");

  // Different format for zero value
  result = result && (FormatFloat("0.0", 0.0D) == "0,0");
  result = result && (FormatFloat("0.0;-0.0;\"Nothing\"", 0.0D) == "Nothing");
  return result;
}

} // class dbsc_formatImplementation

}  // namespace dbsc_format