c# – 如何等待await / async方法完成

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我有以下Async方法：

private async void ProcessSearch()
{
    // get catalogs on first search
    if (_invoiceTypes == null && _invoiceAccounts == null)
    {
        var confWcf = new Data.ConfigurationWCF();
        _invoiceTypes = await confWcf.GetInvoiceTypesAsync(MainForm.State.Entity);
        _invoiceAccounts = await confWcf.GetInvoiceAccountsAsync(MainForm.State.Entity);
        confWcf.Dispose();
    }

    var seekWcf = new DataSeekWCF();
    _ds = await seekWcf.SearchInvoiceAdminAsync(new Guid(cboEmployer.Value.ToString()), new Guid(cboGroup.Value.ToString()), txtSearchInvoiceNumber.Text, chkSearchLike.Checked, txtSearchFolio.Text, Convert.ToInt32(txtYear.Value));
    seekWcf.Dispose();

    if (_ds != null)
    {
        SetupInvoiceGrid();
    }
}

在_invoiceTypes,_invoiceAccounts和_ds完成之前,我不想执行SetupInvoiceGrid.

任何线索？我做得对吗？我应该使用Task而不是等待吗？

我已经想出了这个代码似乎正在工作,看起来很好,但我不知道它是否正确：

private void btnSearch_Click(object sender, EventArgs e)
{
    lock (lockObj)
    {
        if (_isBusy)
            return;
        else
            _isBusy = true;
    }

    ShowPleaseWait(Translate("Searching data. Please wait..."));
        if (_invoiceTypes == null && _invoiceAccounts == null)
        {
            var t = GetCatalogs();
            t.ContinueWith(t2 =>
            {
                if (t.IsCompleted) ProcessSearch();
            });
        }
        else
        {
            ProcessSearch();
        }
}

private async Task GetCatalogs()
{
    // get catalogs on first search
    Data.ConfigurationWCF confWcf = new Data.ConfigurationWCF();
    var task1 = confWcf.GetInvoiceTypesAsync(1);
    var task2 = confWcf.GetInvoiceAccountsAsync(1);
    confWcf.Dispose();

    await Task.WhenAll(task1, task2);

    _invoiceTypes = task1.Result;
    _invoiceAccounts = task2.Result;

    if (_invoiceTypes != null)
    {
        cboInvoiceType.DataSource = _invoiceTypes.Tables["invoice_types"];
        cboInvoiceType.DisplayMember = "description";
        cboInvoiceType.ValueMember = "code";
    }

}

private async void ProcessSearch()
{
    var seekWcf = new Data.SeekWCF();
    _ds = await seekWcf.SearchInvoiceAdminAsync(new Guid(cboEmployer.Value.ToString()), new Guid(cboGroup.Value.ToString()), txtSearchInvoiceNumber.Text, chkSearchLike.Checked, txtSearchFolio.Text, Convert.ToInt32(txtYear.Value));
    seekWcf.Dispose();

    if (_ds != null)
    {
        SetupInvoiceGrid();
    }
    HidePleaseWait();
}

解决方法:

我回答了关于如何处理ProcessSearchAsync本身here的完成的原始(？)问题.

要并行运行任务(如评论中所述),这里修改了代码,因为invoiceTypes == null和_invoiceAccounts == null检查,它会变得有点复杂.注意下面实现检查的方式稍微改变了逻辑(之前只有当_invoiceTypes和_invoiceAccounts都为null时才会调用WCF – 如果只有其中一个为null,那么它是什么？)：

private async Task ProcessSearchAsync()
{

    Data.ConfigurationWCF confWcf = new Data.ConfigurationWCF();
    Task</*typeof _invoiceTypes*/> t1;
    Task</*typeof _invoiceAccounts*/> t2;

    if (_invoiceTypes == null)
        t1 = confWcf.GetInvoiceTypesAsync(MainForm.State.Entity);
    else
    {
        var tsc1 = new TaskCompletionSource</*typeof _invoiceTypes*/>();
        t1 = tsc1.Task;
        tsc1.SetResult(_invoiceTypes);
    }

    if ( _invoiceAccounts == null )
        t2 = confWcf.GetInvoiceAccountsAsync(MainForm.State.Entity);
    else
    {
        var tsc2 = new TaskCompletionSource</*typeof _invoiceAccounts*/>();
        t2 = tsc2.Task;
        tsc2.SetResult(_invoiceAccounts);
    }


    DataSeekWCF seekWcf = new DataSeekWCF();
    Task</*typeof _ds*/> t3 = seekWcf.SearchInvoiceAdminAsync(new Guid(cboEmployer.Value.ToString()), new Guid(cboGroup.Value.ToString()), txtSearchInvoiceNumber.Text, chkSearchLike.Checked, txtSearchFolio.Text, Convert.ToInt32(txtYear.Value));

    await Task.WhenAll(new Task[] {t1, t2, t3});
    _invoiceTypes = t1.Result;
    _invoiceAccounts = t2.Result;
    ds = t3.Result;

    if (_ds != null)
    {
        SetupInvoiceGrid();
    }

    confWcf.Dispose();
    seekWcf.Dispose();
}

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