hope its something simple stupid, but I am spinning my wheels.
I have a Surface Pro 4, Windows 10 and using Visual Studio 2013 Professional.
Developing WPF using C# 4.5.
In summary, all I am trying to do a simple camera capture to save an image without resorting to other 3rd party libraries I have no control over. The rest of this post are details of other research findings that I HAVE looked into and tried working out and what has failed and what such message from the compiler.
Again, simple camera, capture picture, save to disk, but all the async-await options appear to throw compiler errors.
EDIT 1 SAMPLE CODE
Here is code from the WPF form. I do not even have any control in the form as I can not even get the 'await' to compile.
using System;
using Windows.Media.Capture;
using System.Windows;
namespace CameraCapture
{
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
JustDoIt();
}
private MediaCapture _mediaManager;
private async void JustDoIt()
{
//initialize mediacapture with default camera
_mediaManager = new MediaCapture();
await _mediaManager.InitializeAsync();
if (_mediaManager == null)
MessageBox.Show("Failed Initialize");
await _mediaManager.StartPreviewAsync();
}
}
}
And my project also has per other links researched from below, the dlls for
System.Runtime.dll and
System.Runtime.WindowsRuntime.dll
Compile error for each of the 'await'
Error 1 'await' requires that the type 'Windows.Foundation.IAsyncAction' have a suitable GetAwaiter method. Are you missing a using directive for 'System'?
and I have "using System;" as the first line. Is there some other "await" going on when using WinRT vs default System include?
END OF EDIT
I started with https://msdn.microsoft.com/en-us/library/windows/apps/windows.media.capture.cameracaptureui.aspx CameraCaptureUI class
I then found this link https://www.eternalcoding.com/?p=183 How to use specific WinRT API from Desktop apps I tried going through all the steps as outlined and getting errors associated with
await ... have a suitable GetAwaiter method.
So, I looked up about asynch and await and came across
How and When to use `async` and `await`
how and when to use async and await.
So, I scrapped the first camera capture project, started a new, and did that version that has simple thread.sleep delay to show the concept of asynch / await. That part works.
So now, I add back the reference to the project and manually edit to add the
<PropertyGroup>
<TargetPlatformVersion>8.0</TargetPlatformVersion>
</PropertyGroup>
to expose the References expose the Windows / Core per the first link and then getting access to the Windows.Media, Windows.Storage. I add in just the first little bit of code about the CameraCaptureUI and CaptureFileAsync as just a starting point such as...
private async void Camera1()
{
var cameraUi = new Windows.Media.Capture.CameraCaptureUI();
var capturedMedia = await cameraUi.CaptureFileAsync(Windows.Media.Capture.CameraCaptureUIMode.Video);
if (capturedMedia == null)
return;
MessageBox.Show("Valid Camera");
}
and get a compile error about:
'await' requires that the type 'Windows.Foundation.IAsyncOperation' have a suitable GetAwaiter method. Are you missing a using directive for 'System'?
Also, back to the original Windows version attempt via
private async void Camera2()
{
CameraCaptureUI dialog = new CameraCaptureUI();
Windows.Foundation.Size aspectRatio = new Windows.Foundation.Size(16, 9);
dialog.PhotoSettings.CroppedAspectRatio = aspectRatio;
StorageFile file = await dialog.CaptureFileAsync(CameraCaptureUIMode.Photo);
if (file == null)
return;
MessageBox.Show("Valid Storage File Captured");
}
I even have System.Runtime and System.RunTime.WindowsRuntime as references to the project but still fail on compile.
What am I missing. I know things change between different versions such as Windows 8.1 and Windows 10, and upgrades to features / libraries, but why await works one way, but not another.
