await foreach

Context: await foreach iterates over an IAsyncEnumerable<T> asynchronously, awaiting each element before the loop body executes.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

public class Example
{
    public static async Task Main()
    {
        await foreach (var item in GetDataAsync())
        {
            Console.WriteLine(item);
        }
    }

    private static async IAsyncEnumerable<int> GetDataAsync()
    {
        for (int i = 0; i < 5; i++)
        {
            await Task.Delay(100);
            yield return i;
        }
    }
}

Cancellation

You can pass a CancellationToken to the GetAsyncEnumerator method.

var cts = new CancellationTokenSource();
await foreach (var item in GetDataAsync().WithCancellation(cts.Token))
{
    // ...
}

Real-world usage example

Processing paginated API responses: Each page is fetched asynchronously, and you await foreach over the pages.

Example: .NET Async Streams documentation

await foreach

Cancellation

Real-world usage example

Related sections