Question 374465 in Visual Studio Code Question posted in
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Visual Studio Code – C# Maui iOS GetAwaiter Operation is not supported on this platform

I’m trying to use the GoogleAPI Roads library to snap to road.
The call is async:
GoogleMaps.Roads.SnapToRoad.QueryAsync(request).GetAwaiter();

But when I run the code I get the error ‘Operation is not supported on this platform’.
The original code was:

var response = await GoogleMaps.Roads.SnapToRoad.QueryAsync(request).Result;
But that required the void that makes that call to be async, so that just moves the problem to earlier in the callstack.

I cannot use OnCompleted either, as that requires a call to GetAwaiter first.
I’m not sure what I’m doing wrong here.

The device is running iOS 16.7.4, Xcode 15.2 and Visual Studio 17.8.6

EDIT: Updated with async task function

Still getting the same error on:

var response = await GoogleMaps.Roads.SnapToRoad.QueryAsync(request);

This is what I got now:

public static async Task<List<Position>> snapToRoad(List<Position> gpsPos)
{
    List<Position> result = new List<Position>();
    List<List<Position>> subLists = ListExtensions.ChunkBy<Position>(gpsPos, 100);
    foreach (List<Position> gPos in subLists)
    {
        Coordinate[] requestPath = gPos
        .Select(geo => new Coordinate((double)geo.Latitude, (double)geo.Longitude))
        .ToArray();

        SnapToRoadsRequest request = new SnapToRoadsRequest
        {
            Key = MAPS_KEY,
            Path = requestPath
        };
        var response = await GoogleMaps.Roads.SnapToRoad.QueryAsync(request);
        foreach (SnappedPoint sp in response.SnappedPoints)
        {
            result.Add(new Position(sp.Location.Latitude, sp.Location.Longitude));
        }
    }

    return result;
}

It’s calld by a new thread that is started by a button click event:

async void btnSomething_Click(object sender, EventArgs e)
{
    Thread trd = new Thread(async () =>
    {
        var snapped = await MapUtils.snapToRoad(rawCordList);
    });
    trd.IsBackground = true;
    trd.Start();
}
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Turns out, it was an issue with the library. It tries to set a proxy and that is not supported by Maui on iOS at this time.


  2. 0

    Since the method returns an awaitable Task, you should await it and not call GetAwaiter() or access the Result directly. This should be done in a method that also returns an awaitable Task ("async-all-the-way", Why use Async/await all the way down):

    public async Task SnapAsync()
{
    // create request
    // ...

    var response = await GoogleMaps.Roads.SnapToRoad.QueryAsync(request);

    // handle response
    // ...
}
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