windows rt 扫描二维码

项目中使用的是ZXing.net，应用商店程序。使用到的dll是ZXing.winmd。

大致思路为，使用MediaCapture捕获图片。获取到CapturePhotoToStreamAsync流，然后将其转换为WriteableBitmap，使用ZXing进行解析，该项目主要是为了获取二维码类型和文本值。

代码如下：

 1         private async void CaptureBarcode()
 2         {
 3             mediaCapture = new MediaCapture();
 4             await mediaCapture.InitializeAsync();
 5             captureElement.Source = mediaCapture;
 6             await mediaCapture.StartPreviewAsync();
 7             Result result = default(Result);
 8             while (true)
 9             {
10                 IRandomAccessStream stream = new InMemoryRandomAccessStream();
11                 await mediaCapture.CapturePhotoToStreamAsync(ImageEncodingProperties.CreatePng(), stream);
12                 await stream.FlushAsync();
13                 stream.Seek(0);
14                 IBarcodeReader reader = new BarcodeReader();
15                 WriteableBitmap bitmap = new WriteableBitmap(640, 480);
16                 bitmap.SetSource(stream);
17                 if (bitmap == null)
18                     continue;
19                 result = reader.Decode(bitmap);
20                 if (result != null)
21                     break;
22                 continue;
23             }
24             if (result == default(Result))
25                 return;
26             await mediaCapture.StopPreviewAsync();
27             jsonFunc("{ "type":"" + result.BarcodeFormat + "","code":"" + result.Text + ""}");
28         }