使用时间戳捕获

本文介绍了使用时间戳捕获-为什么ImageStream消失了?！的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我找不到我遗漏的东西.请帮助我

I can't find some i misstake or missing. Please help me

出现时间戳，相机图像消失.

Timestamp appear, Camera image disappear.

非常感谢，请....

Thankyou so much, Please....

void camera_CaptureImageAvailable(object sender, Microsoft.Devices.ContentReadyEventArgs e) { startVal++; string filename = startVal.ToString(); { // Decode the JPEG stream. Deployment.Current.Dispatcher.BeginInvoke(delegate() { // load photo to writable bitmap WriteableBitmap writeableBitmap = PictureDecoder.DecodeJpeg(e.ImageStream); var renderText = new TextBlock { Text = "TimeStamp - " + DateTime.Now.ToString(), FontSize = 72, Foreground = new SolidColorBrush(Colors.White), FontWeight = FontWeights.Black, Width = 500, Height = 100 }; writeableBitmap.Render(renderText, new TranslateTransform() { X = 100, Y = 300 }); writeableBitmap.Invalidate(); using (var ms = new MemoryStream()) { writeableBitmap.SaveJpeg(ms, 1024, 768, 0, 100); ms.Seek(0, SeekOrigin.Begin); mediaLibrary.SavePictureToCameraRoll(filename, ms); } e.ImageStream.Close(); }); Deployment.Current.Dispatcher.BeginInvoke(delegate(){textBoxStatus.Text = "Image saved to Library";}); } } /* Code below is work */ /* void camera_CaptureImageAvailable(object sender, Microsoft.Devices.ContentReadyEventArgs e) { startVal++; string filename = startVal.ToString(); mediaLibrary.SavePictureToCameraRoll(filename, e.ImageStream); Deployment.Current.Dispatcher.BeginInvoke(delegate() { textBoxStatus.Text = "Image saved to Library"; }); } */

推荐答案

在渲染TextBlock之前向Invalidate()添加一个额外的调用:

Add an extra call to Invalidate() before rendering the TextBlock: WriteableBitmap writeableBitmap = PictureDecoder.DecodeJpeg(e.ImageStream); writeableBitmap.Invalidate(); var renderText = new TextBlock