using System;

    using System;

    using System.Collections.Concurrent;

    using System.Collections.Generic;

    using System.Linq;

    using System.Text;

    using System.Threading;

    using System.Threading.Tasks;

using System.Text.RegularExpressions;

​

​

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        IsASCII("Paul Schröder");

        Console.WriteLine(IsASCII("Paul Schröder"));

        Console.WriteLine(IsASCII("Paul Schrder"));

​

string s = "søme string";

s = Regex.Replace(s, @"[^\u0000-\u007F]+", string.Empty);

    }

        public static bool IsASCII(string value)

        {

            // ASCII encoding replaces non-ascii with question marks, so we use UTF8 to see if multi-byte sequences are there

            return Encoding.UTF8.GetByteCount(value) == value.Length;

        }

}