Test if string is a guid without throwing exceptions?

by

Performance Benchmarks

Catch exception:
   10,000 good:    63,668 ticks
   10,000 bad:  6,435,609 ticks

Regex Pre-Screen:
   10,000 good:   637,633 ticks
   10,000 bad:    717,894 ticks

COM Interop CLSIDFromString
   10,000 good:   126,120 ticks
   10,000 bad:     23,134 ticks

COM Intertop (Fastest) Answer:

/// <summary>
/// Attempts to convert a string to a guid.
/// </summary>
/// <param name="s">The string to try to convert</param>
/// <param name="value">Upon return will contain the Guid</param>
/// <returns>Returns true if successful, otherwise false</returns>
public static Boolean TryStrToGuid(String s, out Guid value)
{
   //ClsidFromString returns the empty guid for null strings   
   if ((s == null) || (s == ""))   
   {      
      value = Guid.Empty;      
      return false;   
   }

   int hresult = PInvoke.ObjBase.CLSIDFromString(s, out value);
   if (hresult >= 0)
   {
      return true;
   }
   else
   {
      value = Guid.Empty;
      return false;
   }
}


namespace PInvoke
{
    class ObjBase
    {
        /// <summary>
        /// This function converts a string generated by the StringFromCLSID function back into the original class identifier.
        /// </summary>
        /// <param name="sz">String that represents the class identifier</param>
        /// <param name="clsid">On return will contain the class identifier</param>
        /// <returns>
        /// Positive or zero if class identifier was obtained successfully
        /// Negative if the call failed
        /// </returns>
        [DllImport("ole32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, PreserveSig = true)]
        public static extern int CLSIDFromString(string sz, out Guid clsid);
    }
}

Bottom line: If you need to check if a string is a guid, and you care about performance, use COM Interop.

If you need to convert a guid in String representation to a Guid, use

new Guid(someString);

More Related Contents:

  1. Parse string to DateTime in C#
  2. Identify if a string is a number
  3. How to escape braces (curly brackets) in a format string in .NET
  4. How do I parse a string with a decimal point to a double?
  5. Evaluate string with math operators [duplicate]
  6. Convert JSON String to JSON Object c#
  7. Casting vs Converting an object toString, when object really is a string
  8. Remove file extension from a file name string
  9. Is there any generic Parse() function that will convert a string to any type using parse?
  10. Does C# have a String Tokenizer like Java’s?
  11. Split and cut string in C# [closed]
  12. How to cut up a string from an input file with Regex or String Split, C#?
  13. Compression/Decompression string with C#
  14. How do I read a specified line in a text file?
  15. C# List to string with delimiter
  16. What is the difference between a mutable and immutable string in C#?
  17. Verifying that a string contains only letters in C#
  18. Get file name from URI string in C#
  19. Memory Efficiency and Performance of String.Replace .NET Framework
  20. Parse C# string to DateTime
  21. How to read a .NET Guid into a Java UUID
  22. What’s a good way of doing string templating in .NET?
  23. Convert binary string into integer
  24. C# hex to ascii
  25. Why only literal strings saved in the intern pool by default?
  26. Search for a string in Enum and return the Enum
  27. Checking for null before ToString()
  28. Get text between 2 html tags c#
  29. Best algorithm for evaluating a mathematical expression?
  30. splitting a string based on multiple char delimiters

Leave a Comment