THIS ARTICLE WILL SHOW YOU HOW TO TEST DATE INPUTS FOR CONSISTENCY

private static void SetSelected(string Date)
  {   
   string[] ResultList;
   Regex DateSplitter = new Regex("^\\d{4,4}\\/\\d{1,2}\\/\\d{1,2}$");//YYYY/MM/DD
   if(DateSplitter.IsMatch(Date))
   {
    char divider = '/';
    ResultList = Date.Split(divider);
    int SelectedYear = Int32.Parse(ResultList[0]);
    int SelectedMonth = Int32.Parse(ResultList[1]);
    int SelectedDay = Int32.Parse(ResultList[2]);
    int CompareDay=0;
    if(SelectedMonth<=12 )
    {
     CompareDay=DateTime.DaysInMonth(SelectedYear,SelectedMonth);    
    }
    else
    {
     Console.WriteLine("Invalid Date");
     return ;
    }
    if(SelectedDay >CompareDay)
    {
     Console.WriteLine("Invalid Date");
     return ;
    }
    else if(SelectedYear>=2100 || SelectedYear <= 1900 )
    {
     Console.WriteLine("Invalid Date");
     return ;
    }
    else
    {
     Console.WriteLine("Valid");
    }
   }
   else
   {
    Console.WriteLine("InValid Date");
   }
  }

PASS A STRING DATE TO THISMETHOD AND IT WILL TELL YOU WHETHER YOU HAD ENTERED CORRECT DATE OR NOT NOTE: YOU MUST ENTER YYYY/MM/DD FORMAT YOU CAN CHANGE THE CODE FOR OTHER DATE FORMATS