How do i replace accents (german) in .NET

Question

I need to replace accents in the string to their english equivalents

for example

ä = ae

ö = oe

Ö = Oe

ü = ue

I know to strip

Answer 1

This class removes diacritic characters (é, ì, è, etc.) and replaces umlauts and the German "ß" with their equivalents "ae (ä)", "oe (ö)", "ue (ü)" and "ss (ß)".

public sealed class UmlautConverter
{
    private Dictionary converter = new Dictionary()
    {
        {  'ä', "ae" },
        {  'Ä', "AE" },
        {  'ö', "oe" },
        {  'Ö', "OE" },
        {  'ü', "ue" },
        {  'Ü', "UE" },
        {  'ß', "ss" }
    };

    string value = null;
    public UmlautConverter(string value)
    {
        if (!string.IsNullOrWhiteSpace(value))
        {
            this.value = value;
        }
    }
    public string RemoveDiacritics()
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return null;
        }

        string normalizedString = this.value.Normalize();

        foreach (KeyValuePair item in this.converter)
        {
            string temp = normalizedString;
            normalizedString = temp.Replace(item.Key.ToString(), item.Value);
        }

        StringBuilder stringBuilder = new StringBuilder();

        for (int i = 0; i < normalizedString.Length; i++)
        {
            normalizedString = normalizedString.Normalize(NormalizationForm.FormD);
            string c = normalizedString[i].ToString();
            if (CharUnicodeInfo.GetUnicodeCategory(Convert.ToChar(c)) != UnicodeCategory.NonSpacingMark)
            {
                stringBuilder.Append(c);
            }
        }
        return stringBuilder.ToString();
    }

    public bool HasUmlaut()
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return false;
        }

        foreach (KeyValuePair item in this.converter)
        {
            if (this.value.Contains(item.Key.ToString()))
            {
                return true;
            }
        }

        return false;
    }
}

Usage:

Console.WriteLine(new UmlautConverter("Nürnberger Straße").RemoveDiacritics()); // Nuernberger Strasse

        Console.WriteLine(new UmlautConverter("Größenwahn").RemoveDiacritics()); // Groessenwahn
        Console.WriteLine(new UmlautConverter("Übermut").RemoveDiacritics()); // UEbermut
        Console.WriteLine(new UmlautConverter("Università").RemoveDiacritics()); // Universita
        Console.WriteLine(new UmlautConverter("Perché").RemoveDiacritics());// Perche
        Console.WriteLine(new UmlautConverter("être").RemoveDiacritics()); // etre

There is a minor bug in the "Übermut" case replacing "Ü" with "UE" instead of Ue". But this can be easily fixed. Enjoy :)