using System.Text.RegularExpressions;
using System.Diagnostics;
private static readonly Regex cjkCharRegex = new Regex(@"\p{IsThai}");
public static bool IsThai(char c)
return cjkCharRegex.IsMatch(c.ToString());
public static void Main()
var regex = new Regex("([\u0E00-\u0E7F])");
var stopWatch = new Stopwatch();
Console.WriteLine(regex.IsMatch("กรุงเทพมหานคร"));
Console.WriteLine(stopWatch.Elapsed.TotalMilliseconds + "ms");
char[] sometext = "กรุงเทพมหานคร".ToCharArray();
if (sometext.All(z => IsThai(z))) Console.WriteLine("true");