A few summaries of c sharp common regular expressions

using   System;  
using   System.Text.RegularExpressions;  

namespace   CommonTools  
{  
/**////   < summary >  
/// a summary of   RegexLib  .  
///   < /summary >  
public   class   RegexLib  
{  

// verify Email address  
public   static   bool   IsValidEmail(string   strIn)  
{  
//   Return   true   if   strIn   is   in   valid   e-mail   format.  
return   Regex.IsMatch(strIn,   @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");  
}  
// the date form of dd-mm-yy   replaces the date form of   mm/dd/yy  .  
public   static   string   MDYToDMY(String   input)  
{  
return   Regex.Replace(input,"\\b(?\\d{1,2})/(?\\d{1,2})/(?\\d{2,4})\\b","${day}-${month}-${year}");  
}  
// verify the decimal  
public   static   bool   IsValidDecimal(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"[0].\d{1,2}|[1]");  
}  
// verify that the number is  
public   static   bool   IsValidTel(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"(\d+-)?(\d{4}-?\d{7}|\d{3}-?\d{8}|^\d{7,8})(-\d+)?");  
}  
// verify year month date  
public   static   bool   IsValidDate(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"^2\d{3}-(?:0?[1-9]|1[0-2])-(?:0?[1-9]|[1-2]\d|3[0-1])(?:0?[1-9]|1\d|2[0-3]):(?:0?[1-9]|[1-5]\d):(?:0?[1-9]|[1-5]\d)$");  
}  
// verify suffix  
public   static   bool   IsValidPostfix(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"\.(?i:gif|jpg)$");  
}  
// verify that the characters are between 4 and 12  
public   static   bool   IsValidByte(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"^[a-z]{4,12}$");  
}  
// verify IP  
public   static   bool   IsValidIp(string   strIn)  
{  
return   Regex.IsMatch(strIn,@"^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])$");  
}  

}  
}