public IEnumerable <Task <SensorDto> > OpenStream(IEnumerable <string> ids)
{
while (true)
{
foreach (var id in ids)
{
yield return(SensorData.GetSensorAsync(id));
}
}
}
public async Task Tasks_FromAsync_Linq()
{
var ids = new string[] { "iddqd", "idkfq", "abba5", "acdc1" };
var tasksLinq = ids.Select(e => SensorData.GetSensorAsync(e)).ToList();
var results = await Task.WhenAll(tasksLinq);
// Select is lazy, but now tasksLinq is a List
// Try what happes without .ToList() and with it
var over10Sensors = tasksLinq.Where(e => e.Result.Data > 10).ToList();
}
public async Task Lazy_Class()
{
var sensor = new Lazy <Task <SensorDto> >(async() =>
{
Trace.WriteLine("Fetching data");
return(await SensorData.GetSensorAsync("abba5"));
});
Assert.False(sensor.IsValueCreated);
var data = await sensor.Value;
var dataOther = await sensor.Value;
}
public void ReferenceType()
{
var sensorRequest = new SensorRequest {
Id = "iddqd"
};
var getData = new Func <SensorRequest, Task <SensorDto> >(async request =>
{
await Task.Delay(1000);
return(await SensorData.GetSensorAsync(request.Id));
});
var sensorTask = getData(sensorRequest);
sensorRequest.Id = "idkfa";
var result = sensorTask.Result;
}
public async Task Linq_Select_Lazy()
{
// 07_Linq has and example of LINQ Select. This example shows more complicated case with API requests
// Find first sensor with data value under 23
var sensorIds = new[] { "iddqd", "idkfa", "abba5", "acdc1" };
// Have to use own extension method as Where/First etc. do not support async
var item = await sensorIds.Select(async id =>
{
var data = await SensorData.GetSensorAsync(id);
Trace.WriteLine(JsonConvert.SerializeObject(data));
return(data);
})
.FirstOrDefaultAsync(async s => (await s).Data < 23);
Trace.WriteLine($"First item: {JsonConvert.SerializeObject(item)}");
}
public void SensorId()
{
var selectedSensor = "iddqd";
var getData = new Func <Task <SensorDto> >(async() =>
{
await Task.Delay(1000);
return(await SensorData.GetSensorAsync(selectedSensor));
});
var sensorTask = getData();
selectedSensor = "idkfa";
var result = sensorTask.Result;
// Fix
// var getData = new Func<string Task<SensorDto>>(async sensorId =>
}
public async Task Tasks_FromAsync()
{
var ids = new string[] { "iddqd", "idkfq", "abba5", "acdc1" };
var tasks = new List <Task <double> >();
foreach (var id in ids)
{
var dataTask = SensorData.GetDataAsync(id);
tasks.Add(dataTask);
}
var results = await Task.WhenAll(tasks);
var tasksLinq = ids.Select(e => SensorData.GetSensorAsync(e)).ToList();
var results2 = await Task.WhenAll(tasksLinq);
// Select is lazy, but now tasksLinq is a List
var high = tasksLinq.Where(e => e.Result.Data > 10).ToList();
}
