C# Remove special characters

Question

I want to remove all special characters from a string. Allowed characters are A-Z (uppercase or lowercase), numbers (0-9), underscore (_), white space ( ), pecentage(%) or the d

Answer 1

This is how my version might look.

StringBuilder sb = new StringBuilder();
foreach (char c in input)
{
    if (Char.IsLetterOrDigit(c) ||
        c == '.' || c == '_' || c == ' ' || c == '%')
        sb.Append(c);
    }
}
return sb.ToString();