MVC 6 异步操作

所以我已经开始了将我的nHibernate网站转换为使用Dapper的概念验证。

我正在处理的操作方法现在似乎正在工作：

public IActionResult About()
{
    ViewData["Message"] = "Your application description page.";
    var invoice = invoiceRepo.GetInvoiceAsync(19992031);
    var allInvoices = invoiceRepo.GetAllInvoicesAsync();
    var model = new Models.AboutModel
    {
        Invoice = invoice.Result,
        AllInvoices = allInvoices.Result
    };
    return View(model);
}

但后来我意识到/记住了，为了使它是异步的，我需要对动作进行Task，如下所示：

public Task<IActionResult> About()
{
    ViewData["Message"] = "Your application description page.";
    var invoice = invoiceRepo.GetInvoiceAsync(19992031);
    var allInvoices = invoiceRepo.GetAllInvoicesAsync();
    var model = new Models.AboutModel
    {
        Invoice = invoice.Result,
        AllInvoices = allInvoices.Result
    };
    return View(model);
}

但是一旦我这样做，它告诉我我需要等待一些东西。在我看到的所有示例中，它只显示了如下所示的内容：

var result = await repo.Get(param);

但是我已经在我的存储库中进行了"等待"。

public async Task<Invoice> GetInvoiceAsync(int invoiceId)
{
    const string query = "select InvoiceId, Name [InvoiceName] from dbo.Invoice where InvoiceId = @invoiceId";
    using (var conn = GetConnection())
    {
        var dp = new DynamicParameters();
        dp.Add("@invoiceId", invoiceId);
        await conn.OpenAsync();
        var invoiceResult = await conn.QueryAsync<Invoice>(query, dp, null, 30, CommandType.Text);
        var invoice = invoiceResult.SingleOrDefault();
        return invoice;
    }
}
public async Task<List<Invoice>> GetAllInvoicesAsync()
{
    const string query = "select InvoiceId, Name [InvoiceName] from dbo.Invoice where SalesPeriodId >= 17";
    using (var conn = GetConnection())
    {
        await conn.OpenAsync();
        var invoiceResult = await conn.QueryAsync<Invoice>(query, null, null, 30, CommandType.Text);
        var invoices = invoiceResult.Take(1000).ToList();
        return invoices;
    }
}

因此，我切换到异步的全部意义在于能够异步执行我的两个调用，然后在返回时将结果合并在一起。

如何在具有Task<IActionResult>的情况下更改控制器操作以异步执行此操作？喜欢这个：

public Task<IActionResult>About() {}

更新：那这是正确的吗？

public async Task<IActionResult> About()
{
    ViewData["Message"] = "Your application description page.";
    var invoice = invoiceRepo.GetInvoiceAsync(19992031);
    var allInvoices = invoiceRepo.GetAllInvoicesAsync();
    var model = new Models.AboutModel
    {
        Invoice = await invoice,
        AllInvoices = await allInvoices
    };
    return View(model);
}

这会异步（并行）执行两个存储库调用吗？