mask all digits except first 6 and last 4 digits of a string( length varies )

Question

I have a card number as a string, for example:

string  ClsCommon.str_CardNumbe r = \"3456123434561234\";

The length of this card number can

Answer 1

Try this one. Simple and straight forward.

public static class StringExtensions
{
    public static string Masked(this string source, int start, int count)
    {
        return source.Masked('x', start, count);
    }

    public static string Masked(this string source, char maskValue, int start, int count)
    {
        var firstPart = source.Substring(0, start);
        var lastPart = source.Substring(start + count);
        var middlePart = new string(maskValue, count);

        return firstPart + middlePart + lastPart;
    }
}