Validating date in MMDDYYYY format in C#

Hi,

I am writing a small piece of code that validates a given date against the MMDDYYYY format

Here is my code:

//Validate string date with string date_format MMDDYYYY

public bool validate_datet(string date, string date_format)

      {
                  try
                  {
                        DateTimeFormatInfo dtfi = new DateTimeFormatInfo();
                              
                        dtfi.LongDatePattern = date_format;

                        DateTime dt = DateTime.ParseExact(date,date_format,dtfi);
                                          }
                  catch(Exception)
                  {
                        
                                                   return false;
      
                  }
            return true;
                    }

This function returns false even when I pass in a valid date in the MMDDYYYY format such as 06251966. Could anybody tell me what it is that  I am doing wrong here..anybody........

Thanks
Praveen