Getting Events in Windows Forms app

Cloud
1

I’m trying to follow the Win SDK documentation, but its too sparse for me to follow (my c#-fu is weak).
I have my windows Form app successfully logging in, retrieving my device list and their published variables, and I can send data to my devices - but i can’t figure out how to subscribe to the event stream.

If I copy the example code :

private void onEvent(object sender, ParticleEventResponse particeEvent)
{
  Debug.WriteLine($"Got Event {particeEvent.Name} with data {particeEvent.Data}");
}

Guid eventListenerID = ParticleCloud.SharedCloud.SubscribeToAllEventsWithPrefixAsync(onEvent, "temp");

Visual Studio complains about the last line:

Error	CS0236	A field initializer cannot reference the non-static field, method, or property 'Form1.onEvent(object, ParticleEventResponse)'	WGcontrol	C:\Users\paul\documents\visual studio 2015\Projects\WGcontrol\WGcontrol\Form1.cs

What am I doing wrong? I’m putting the code in Form.cs - is that the right place?

Also what is this?

ParticleCloud.SharedCloud.SynchronizationContext = System.Threading.SynchronizationContext.Current;

Do I need it? Where do I put it?

2

How about declaring onEvent as static void?

3

I did try that, but then it complains about

Guid eventListenerID =  ParticleCloud.SharedCloud.SubscribeToAllEventsWithPrefixAsync(onEvent, "temp");

with the error

Error CS0029 Cannot implicitly convert type ‘System.Threading.Tasks.Task<System.Guid>’ to ‘System.Guid’ WGcontrol C:\Users\paul\documents\visual studio 2015\Projects\WGcontrol\WGcontrol\Form1.cs

4

I’m not very familiar with the C# SDK but if you are calling .....Async() functions, would you not use the await keyword with it?

5

I’ve needed to add that to other parts of the example code, but it just creates more errors in this bit. Does not seem to be applicable in this instance.

6

Ok, fresh cup of coffee, and i’ve made it work.

Guid eventListenerID = await ParticleCloud.SharedCloud.SubscribeToAllEventsWithPrefixAsync(onEvent, "temp");

does need the ‘await’ operator, and needs to be located inside a method labelled with ‘async’.

Thanks for the brain prods … :smile:

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