SilverLight 得到文件绝对路径

 public static string GetAbsoluteUrl(string strRelativePath)
        {
            if (string.IsNullOrEmpty(strRelativePath))
                return strRelativePath;

            string strFullUrl;
            if (strRelativePath.StartsWith("http:", StringComparison.OrdinalIgnoreCase)
              || strRelativePath.StartsWith("https:", StringComparison.OrdinalIgnoreCase)
              || strRelativePath.StartsWith("file:", StringComparison.OrdinalIgnoreCase)
              )
            {
                //already absolute
                strFullUrl = strRelativePath;
            }
            else
            {
                //relative, need to convert to absolute
                strFullUrl = System.Windows.Application.Current.Host.Source.AbsoluteUri;
                if (strFullUrl.IndexOf("ClientBin") > 0)
                    strFullUrl = strFullUrl.Substring(0, strFullUrl.IndexOf("ClientBin")) + strRelativePath;
            }

            return strFullUrl;
        }