C# 如何 实现 像VB 的 Format函数 一样的功能 ??

Question

C# 如何 实现 像VB 的 Format函数 一样的功能 ??
如何实现 vb 下面的功能 :
 Format(12, "'D-'#")
为 D-12 Format(12, "#.00")
为 12.00 Dim d As Date
  d = "06-2-6"
  Label2.Text = Format(d, "yyyy-MM-dd")
为 2006-02-06
  Dim d As DateTime
 d = "06-2-3 12:25:23"
'大写H为24小时制
Label2.Text = Format(d, "hh点mm分ss秒")
为12点25分23秒
C# 如何实现??

Answer 1

自带有函数的
例:
DateTime d = Convert.ToDateTime("2006-2-6");
Label2.Text = d.ToString("yyyy-MM-dd");为 2006-02-06

Answer 2

反编译VB的Formatpublic static string Format(object Expression, [Optional] string Style /* = "" */)
{
      string text1;
      try
      {
            double num1;
            float single1;
            IFormatProvider provider1 = null;
            IFormattable formattable1 = null;
            if ((Expression == null) || (Expression.GetType() == null))
            {
                  return "";
            }
            if ((Style == null) || (Style.Length == 0))
            {
                  return Conversions.ToString(Expression);
            }
            IConvertible convertible1 = (IConvertible) Expression;
            TypeCode code1 = convertible1.GetTypeCode();
            if (Style.Length > 0)
            {
                  try
                  {
                        string text2 = null;
                        if (Strings.FormatNamed(Expression, Style, ref text2))
                        {
                              return text2;
                        }
                  }
                  catch (StackOverflowException exception1)
                  {
                        throw exception1;
                  }
                  catch (OutOfMemoryException exception2)
                  {
                        throw exception2;
                  }
                  catch (ThreadAbortException exception3)
                  {
                        throw exception3;
                  }
                  catch (Exception)
                  {
                        return Conversions.ToString(Expression);
                  }
            }
            formattable1 = Expression as IFormattable;
            if (formattable1 == null)
            {
                  code1 = Convert.GetTypeCode(Expression);
                  if ((code1 != TypeCode.String) && (code1 != TypeCode.Boolean))
                  {
                        throw new ArgumentException(Utils.GetResourceString("Argument_InvalidValue1", new string[] { "Expression" }));
                  }
            }
            switch (code1)
            {
                  case TypeCode.Empty:
                        return "";                  case TypeCode.Object:
                  case TypeCode.Char:
                  case TypeCode.SByte:
                  case TypeCode.Byte:
                  case TypeCode.Int16:
                  case TypeCode.UInt16:
                  case TypeCode.Int32:
                  case TypeCode.UInt32:
                  case TypeCode.Int64:
                  case TypeCode.UInt64:
                  case TypeCode.Decimal:
                  case TypeCode.DateTime:
                        return formattable1.ToString(Style, provider1);                  case TypeCode.DBNull:
                        return "";                  case TypeCode.Boolean:
                        return string.Format(provider1, Style, new object[] { Conversions.ToString(convertible1.ToBoolean(null)) });                  case TypeCode.Single:
                        single1 = convertible1.ToSingle(null);
                        if ((Style == null) || (Style.Length == 0))
                        {
                              return Conversions.ToString(single1);
                        }
                        goto Label_01C3;                  case TypeCode.Double:
                        num1 = convertible1.ToDouble(null);
                        if ((Style == null) || (Style.Length == 0))
                        {
                              return Conversions.ToString(num1);
                        }
                        break;                  case (TypeCode.DateTime | TypeCode.Object):
                        goto Label_01F8;                  case TypeCode.String:
                        return string.Format(provider1, Style, new object[] { Expression });                  default:
                        goto Label_01F8;
            }
            if (num1 == 0)
            {
                  num1 = 0;
            }
            return num1.ToString(Style, provider1);
      Label_01C3:
            if (single1 == 0f)
            {
                  single1 = 0f;
            }
            return single1.ToString(Style, provider1);
      Label_01F8:
            text1 = formattable1.ToString(Style, provider1);
      }
      catch (Exception exception4)
      {
            throw exception4;
      }
      return text1;
}

Answer 3

Format(12, "'D-'#")
为  Format(12, "#.00")
为 12.00
string.format("D-{0}",12) //为D-12string.format("{0}.00",12)//为 12.00

Answer 4

textBox1.Text =  string.Format ("{0}.00",2.2);结果是  2.2.00为什么不是 2.20 ??