Validating Guid

This code sample validates a given GUID using regular expressions. The IsGuid takes a string that is a global unique identifier. It checks if it fits the regular expression represented by the isGuid objects and returns a boolean value accordingly.

private static Regex isGuid = new Regex(@"^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$");

public static bool IsGuid(string value)

bool isValid = false;

if (!String.IsNullOrEmpty(value))
if (isGuid.IsMatch(value))
isValid = true;
return isValid;


Author: Paul28 Dec 2010 Member Level: Bronze   Points : 1

VB.Net Version (add to string library):

 Public Const GUIDRegex As String = "^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$"

 Public Shared Function IsGUID(ByVal Expression As String) As Boolean
   Dim isValid As Boolean = False

   If Not String.IsNullOrEmpty(Expression) Then
      Dim match As System.Text.RegularExpressions.Match
      match = System.Text.RegularExpressions.Regex.Match(Expression, GUIDRegex)
      isValid = match.Success
   End If

   Return isValid
 End Function

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