using System;

using System.Globalization;

using System.Linq;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("çãáôõà".RemoveAccents());

    }

}

​

public static class StringExtensions

{

    public static string RemoveAccents(this string text)

    {

        if (string.IsNullOrWhiteSpace(text))

            return text;

​

        text = text.Normalize(NormalizationForm.FormD);

        var chars = text.Where(c => CharUnicodeInfo.GetUnicodeCategory(c) != UnicodeCategory.NonSpacingMark).ToArray();

        return new string(chars).Normalize(NormalizationForm.FormC);

    }

}