C method to verify that a given date in string form is valid

This article demonstrates C#'s method of verifying that a given date in string form is valid. Share with you for your reference. The specific analysis is as follows:

The C# code is used to verify the validity of the date. It also handles the irregular date entered by the user. For example, if the user enters "today", the code will assume that the user is returning today's date

/// <summary>
///  Verify that the date is valid , The irregularity is simply treated 
/// </summary>
/// <param name="date"> The date of </param>
public static bool IsDate(ref string date)
{
  // If it is empty, the validation is considered qualified 
  if (IsNullOrEmpty(date))
  {
 return true;
  }
  // Clear the whitespace in the string to validate 
  date = date.Trim();
  // replace \
  date = date.Replace(@"\", "-");
  // replace /
  date = date.Replace(@"/", "-");
  // If you find a Chinese character " today ", Is the current date 
  if (date.IndexOf(" today ") != -1)
  {
 date = DateTime.Now.ToString();
  }
  try
  {
 // Test for a regular date character with a conversion 
 date = Convert.ToDateTime(date).ToString("d");
 return true;
  }
  catch
  {
 // Returns if a non-number exists in the date string false
 if (!IsInt(date))
 {
   return false;
 }
 #region  Parse the pure numbers 
 // right 8 Bits of pure numbers are parsed 
 if (date.Length == 8)
 {
   // Get year, month and day 
   string year = date.Substring(0, 4);
   string month = date.Substring(4, 2);
   string day = date.Substring(6, 2);
   // Validation of validity 
   if (Convert.ToInt32(year) < 1900 || Convert.ToInt32(year) > 2100)
   {
 return false;
   }
   if (Convert.ToInt32(month) > 12 || Convert.ToInt32(day) > 31)
   {
 return false;
   }
   // Date of joining together 
   date = Convert.ToDateTime(year + "-" + month + "-" + day).ToString("d");
   return true;
 }
 // right 6 Bits of pure numbers are parsed 
 if (date.Length == 6)
 {
   // For years 
   string year = date.Substring(0, 4);
   string month = date.Substring(4, 2);
   // Validation of validity 
   if (Convert.ToInt32(year) < 1900 || Convert.ToInt32(year) > 2100)
   {
 return false;
   }
   if (Convert.ToInt32(month) > 12)
   {
 return false;
   }
   // Date of joining together 
   date = Convert.ToDateTime(year + "-" + month).ToString("d");
   return true;
 }
 // right 5 Bits of pure numbers are parsed 
 if (date.Length == 5)
 {
   // For years 
   string year = date.Substring(0, 4);
   string month = date.Substring(4, 1);
   // Validation of validity 
   if (Convert.ToInt32(year) < 1900 || Convert.ToInt32(year) > 2100)
   {
 return false;
   }
   // Date of joining together 
   date = year + "-" + month;
   return true;
 }
 // right 4 Bits of pure numbers are parsed 
 if (date.Length == 4)
 {
   // For years 
   string year = date.Substring(0, 4);
   // Validation of validity 
   if (Convert.ToInt32(year) < 1900 || Convert.ToInt32(year) > 2100)
   {
 return false;
   }
   // Date of joining together 
   date = Convert.ToDateTime(year).ToString("d");
   return true;
 }
 #endregion
 return false;
  }
}

I hope this article is helpful to your C# program design.