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

Question

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-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.

Answer 1

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 .

Answer 2

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