How can I make xmldataprovider process escaped characters?

Question

I have built a very simple XAML RSS reader in WPF, using the XMLDataProvider to get the RSS data. That XAML looks like this:

<XmlDataProvider x:Key="rssData" XPath="//item" Source="http://www.theglobeandmail.com/?service=rss" IsAsynchronous="True" IsInitialLoadEnabled="True" />

Then, I display the description provided by the RSS feed inside a ListItemTemplate like this (irrelevant details elided):

<TextBlock TextWrapping="Wrap" Text="{Binding XPath=description}"/>

The problem is that any escaped characters in the description come through un-processed. ie: Open letter denounces mayor&146;s plan, etc, etc.

The &146; of course, should be converted to an apostrophe. I could write a binding converter to do this reasonably easily, but I don't think I should have to. What simple thing am I missing?

Thanks in advance for any help.

Sadly there is no straightforward way we can make XAML or WPF understand that **&146;** is an apostrophe. Being XML based the apostrophe is represented as **'** — WPF-it, Sep 16 '11 at 05:39

score 0 · Accepted Answer · answered Sep 16 '11 at 15:42

I'm still hoping that there is a better way, but for now I implemented a value converter, used an HTML decoder and then manually fix characters &145; through &149;. I'm open to better solutions, though!

public class HTMLEscapedCharactersConverter : IValueConverter
{
    private static readonly char[] MapChars = {'\x091', '\x092', '\x093', '\x094'};

    object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var htmlText = value as string;
        if (!string.IsNullOrEmpty(htmlText))
        {
            htmlText = System.Net.WebUtility.HtmlDecode(htmlText);
            if (htmlText.IndexOfAny(MapChars) > 0)
            {
                var decodedText = new StringBuilder(htmlText.Length);
                foreach (var ch in htmlText)
                    switch (ch)
                    {
                        // Windows Code page 1252: http://en.wikipedia.org/wiki/Windows-1252 
                        case '\x091':
                            decodedText.Append('\x2018');
                            break;

                        case '\x092':
                            decodedText.Append('\x2019');
                            break;

                        case '\x093':
                            decodedText.Append('\x201C');
                            break;

                        case '\x094':
                            decodedText.Append('\x201D');
                            break;

                        default:
                            decodedText.Append(ch);
                            break;
                    }
                return decodedText.ToString();
            }
        }

        return htmlText ?? String.Empty;
    }

    object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var s = value as string;
        if (s != null)
        {
            s = WebUtility.HtmlEncode(s);
        }

        return s ?? String.Empty;
    }
}

How can I make xmldataprovider process escaped characters?

1 Answers1