private async void AsyncGetTemplateKey(string apiURL) { var request = HttpWebRequest.CreateHttp(apiURL); byte[] result; using (var response = (await SimpleHttpService.GetResponseAsync(request))) { result = await Task <byte[]> .Run(() => { byte[] buffer = new byte[11]; response.GetResponseStream().Read(buffer, 0, 11); return(buffer); }); } GifDecoder decoder = new GifDecoder(); if (decoder.IsSupportedFileFormat(result)) { this.ContentTemplate = GetDataTemplate("Type:Gif"); } else { this.ContentTemplate = GetDataTemplate("Type:Else"); } this.ApplyTemplate(); }