获取url参数

private static string GetQueryParam(string url,string name)
        {
            if (string.IsNullOrWhiteSpace(url))
            {
                return string.Empty;
            }

            if(!Regex.IsMatch(url, "(http[s]?:\\/\\/)?([^\\/\\s]+\\/)(.*)",RegexOptions.IgnoreCase))
            {
                return string.Empty;
            }

            if (string.IsNullOrWhiteSpace(name))
            {
                return string.Empty;
            }

            var query = new Uri(url).Query.TrimStart('?');
            if (string.IsNullOrWhiteSpace(query))
            {
                return string.Empty;
            }

            Dictionary<string, string> dicQueryString =
                query.Split('&')
                .ToDictionary(c => c.Split('=')[0].ToLower(),
                            c => Uri.UnescapeDataString(c.Split('=')[1]));
            if (!dicQueryString.Keys.Contains(name))
            {
                return string.Empty;
            }
            return dicQueryString[name.ToLower()];
        }