How can I enable a word-breaking function by length without split inside html-encoded special chars

I would like to implement a functionality that insert a word-breaking TAG if a word is too long to appear in a single line.

    protected string InstertWBRTags(string text, int interval)
{
    if (String.IsNullOrEmpty(text) || interval < 1 || text.Length < interval)
    {
        return text;
    }
    int pS = 0, pE = 0, tLength = text.Length;
    StringBuilder sb = new StringBuilder(tLength * 2);

    while (pS < tLength)
    {
        pE = pS + interval;
        if (pE > tLength)
            sb.Append(text.Substring(pS));
        else
        {
            sb.Append(text.Substring(pS, pE - pS));
            sb.Append("&#8203;");//<wbr> not supported by IE 8
        }
        pS = pE;
    }
    return sb.ToString();
}

The problem is: What can I do, if the text contains html开发者_如何学C-encoded special chars? What can I do to prevent insertion of a TAG inside a ß? What can I do to count the real string length (that appears in browser)? A string like ♡♥♡♥ contains only 2 chars (hearts) in browser but its length is 14.

One solution would be to decode the entities into the Unicode characters they represent and work with that. To do that use System.Net.WebUtility.HtmlDecode() if you're in .NET 4 or System.Web.HttpUtility.HtmlDecode() otherwise.

But be aware that not all Unicode character fit in one char.

You need to pass through whole text character by character, when you find a & than you examine what is next, if you reach a # it is quite sure that after this till a column will be a set of number (you can check it also). I such situation you move your iterator to the position of nearest semicolon and increment the counter.

In Java dialect

int count = 0;

        for(int i = 0; i < text.length(); i++) {

            if(text.charAt(i) == '&') {
                i  = text.indexOf(';', i) + 1; // what, from
            }

            count++;

        }

Very simplified version