regex-iframe.cs

private readonly Regex _iframeRegex = new Regex(@"<iframe(.*)src=""(?<url>[^""].*?)""(.*?)/>", RegexOptions.Compiled | RegexOptions.CultureInvariant | RegexOptions.IgnoreCase);

public string Body
{
    get
    {
        return _iframeRegex.Replace(_body, (match) =>
        {
            return string.Format(@"<iframe src=""{0}"" frameborder=""0"" webkitallowfullscreen="""" mozallowfullscreen="""" allowfullscreen=""""></iframe>", match.Groups["url"].Value);
        });
    }
}