MVC 6異步操作

Question

因此，我開始將我的nHibernate網站轉換爲使用Dapper的概念證明。出現

是我的工作

我的操作方法是正確的，現在的工作：

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); 
} 

但後來我意識到/牢記，爲了它是異步的，我需要有Task上行動，像這樣：

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，只要我這樣做，它告訴我，我需要等待的東西。在我見過的所有例子中，它只是顯示了這樣的內容：

var result = await repo.Get(param); 

但是我已經在我的回購中「等待」了。

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; 
    } 
} 

所以我切換到異步整點是能夠返回時，兩者都做我的電話的異步，然後合併在一起的結果。

如何更改我的控制器操作以異步執行此操作，同時擁有Task<IActionResult>？像這樣：

public Task<IActionResult>About() {} 

更新：這是正確的嗎？

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); 
} 

這是否會同時執行兩個回購調用（並行）？

Answer 1

您也需要等待您的控制器。經驗法則：永遠不要說.Result，而是說await。

您還應該聲明您的操作方法爲public async。

更新：這將是異步調用您的存儲庫的正確方法。數據庫調用應該並行進行，因爲兩個任務都是在等待任何事情之前啓動的。您可以隨時通過在DB方法的開始和結束處放置調試日誌並看到您獲得「start 1 start 2 end 1 end 2」或類似的內容而不是「start 1 end 1 start 2 end 2」來查看此內容您的查詢相當慢。