谁能帮我吧这段Delphi7代码翻译程C#代码(100分)

function StrToHex(AStr: string): string;
var
  I : Integer;
  //Tmp: string;
begin
  Result := '';
  For I := 1 to Length(AStr)do
  begin
    Result := Result + Format('%2x', [Byte(AStr[I])]);
  end;
  I := Pos(' ', Result);
  While I <> 0do
  begin
    Result[I] := '0';
    I := Pos(' ', Result);
  end;
end;

function HexToStr(AStr: string): string;
var
  I: Integer;
  CharValue: Word;
begin
  Result := '';
  For I := 1 to Trunc(Length(Astr)/2)do
  begin
    Result := Result + ' ';
    CharValue := TransChar(AStr[2*I-1])*16 + TransChar(AStr[2*I]);
    Result[I] := Char(CharValue);
  end;
end;

function TransChar(AChar: Char): Integer;
begin
  if AChar in ['0'..'9'] then
    Result := Ord(AChar) - Ord('0')
  else
  Result := 10 + Ord(AChar) - Ord('A');
end;