Alternative await foreach

.NET SDK
1

My project use .NET Framework 4.6.1 with C# 7.3 and sdk 3.0.3 of Couchbase.
My C# version is not compatible withawait foreach and the migration of C# cause some problems, there is another way to perform that?

This is my code

var resultDynamic = cluster.QueryAsync<dynamic>($"select meta().id from `my-bucket` LIMIT 10", new Couchbase.Query.QueryOptions()).Result;
await foreach (var row in resultDynamic)
{
       // ....
}

Thanks

2

@Giuseppe_Di_Maria

Certainly, you have several different options.

  1. You can usually add <LangVersion>8</LangVersion> or <LangVersion>Major</LangVersion> to your C# project file and get the support you need, even targetting .NET 4.6.1. The only requirement is a recent version of Visual Studio and/or MSBuild (2019 I believe is the requirement). NuGet packages are used to provide the missing types, which is done automatically by the Couchbase SDK. For more details see IAsyncEnumerable Is Your Friend, Even In .NET Core 2.x - RandomDev

  2. If you’re not worried about memory consumption and streaming the results (i.e. for small query results), you can simply await resultDynamic.ToListAsync() using the extension method from the System.Linq.Async package. This will convert the result to a List<T> which you can iterate using a traditional foreach loop.

  3. If you do want to stream the query results, you can manually write the pattern for await foreach. It’s a bit wordy, but generally equivalent.

var enumerator = resultDynamic.GetAsyncEnumerator(); // You may also want a CancellationToken here
try
{
    while (await enumerator.MoveNextAsync()) // You may also want .ConfigureAwait(false) or a CancellationToken here
    {
        var row = enumerator.Current;

        // Do work here
    }
}
finally
{
    await enumerator.DisposeAsync(); // You may also want .ConfigureAwait(false) here
}