C#

public static class Test
{
    public static T GenericDecodeData<T>(byte[] data, string encRules)
    {
        // ...
        return default(T);
    }

    public static Type GetDownloadType(int id)
    {
        switch (id)
        {
            case DOWNDIRECT: return typeof(DownDirect);
            case DOWNOTHER: return typeof(DownOther);
            case DOWNHEHE: return typeof(DownHehe);
            default: return null;
        }
    }
    public static object DecodeData(Type type, byte[] data, string encRules)
    {
        MethodInfo methodInfo = typeof(Test).GetMethod("GenericDecodeData").MakeGenericMethod(
            new Type[] { type });
        return methodInfo.Invoke(null, new object[] { data, encRules });
    }
}

string.Format("{0:0000-0000-0000}", 123456789012);

System.Console.WriteLine ( System.String.Format("{0:0000-0000-0000}",123456789012) ) ;
System.Console.WriteLine ( 123456789012.ToString("0000-0000-0000") ) ;

dgv.Columns[1].Width = 100;

public int Factorial(int n) {
    if (n<=1) return 1;
    return n*Factorial(n-1);
}

string MyFunction( string val )
{
  if ( val == "test" ) return val; // end of recursion

  // recursive case

  string xyz = ...

  return MyFunction( xyz );
}

----------------------------------
Be excellent to each other

private string MyFunction(string val)
{
//ToDo Calculate xyz

  if(xyz != "test") //<----This condition three times true.
  {
  val = MyFunction(xyz);
  }
  else
  {
  return val;
  }
}