如何返回异步 IEnumerable？

我有以下方法：

public async IEnumerable<string> GetListDriversAsync()
{
   var drives = await graphClient.Drive.Root.Children.Request().GetAsync();
        foreach (var d in drives)
            yield return d.ToString(); 
}

但编译器错误说：

“异步的返回类型必须为 void、Task 或 Task<T>"

当方法是异步时，如何返回 IEnumerable？

另一种方法是可能的C# 8 https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/async-streams。它用IAsyncEnumerable https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.iasyncenumerable-1?view=dotnet-plat-ext-3.0.

public async IAsyncEnumerable<string> GetListDriversAsync()
{
    var drives = await graphClient.Drive.Root.Children.Request().GetAsync();
    foreach (var d in drives)
        yield return d.ToString();
}

它会稍微改变您的签名，这可能是（也可能不是）您的选择。

Usage:

await foreach (var driver in foo.GetListDriversAsync())
{
    Console.WriteLine(driver );
}