Question

我正在使用Simple.Data和SQL Server，我有多个彼此独立的方法。在表单上，我有多个需要填充的下拉列表，我认为这些可以异步填充。我有一个返回实体列表的存储库。

在我的Asp.Net网站上，我逐个调用存储库中的方法并将它们绑定到下拉列表，这里是一个示例代码

private void Initialize()
    {
        LoadTechnologies();
        LoadInstallationTypes();
        LoadProvinces();
        LoadYears();            
    }

    private void LoadTechnologies()
    {
        ddlTechnologies.DataSource = _GizRepository.GetTechnologies();
        ddlTechnologies.DataValueField = "Name";
        ddlTechnologies.DataTextField = "Name";
        ddlTechnologies.Items.Insert(0, new ListItem("All", "-1"));
        ddlTechnologies.DataBind();
    }

    private void LoadInstallationTypes()
    {
        ddlInstallationType.DataSource = _GizRepository.GetInstallationTypes();
        ddlInstallationType.DataValueField = "Type";
        ddlInstallationType.DataTextField = "Type";
        ddlInstallationType.Items.Insert(0, new ListItem("Any", "-1"));
        ddlInstallationType.DataBind();
    }

    private void LoadProvinces()
    {
        ddlProvinces.DataSource = _GizRepository.GetProvinces();
        ddlProvinces.DataValueField = "Name";
        ddlProvinces.DataTextField = "Name";
        ddlProvinces.Items.Insert(0, new ListItem("All", "-1"));
        ddlProvinces.DataBind();
    }

    private void LoadYears()
    {
        ddlYearFrom.DataSource = _GizRepository.GetYears();
        ddlYearFrom.DataValueField = "Year";
        ddlYearFrom.DataTextField = "Year";
        ddlYearFrom.DataBind();

        ddlYearTo.DataSource = _GizRepository.GetYears();
        ddlYearTo.DataValueField = "Year";
        ddlYearTo.DataTextField = "Year";
        ddlYearTo.DataBind();
    }

您可以从上面的代码中看到，我所做的就是从存储库中获取一些列表并将它们绑定到下拉列表中。我想异步执行这些方法而不是同步，请指导它是如何完成的？

Answer 1

使用async / await但不从每个例程返回任务。结果是他们同时运行所有等待他们自己的io然后在UI线程上完成。

private void Initialize()
    {
        LoadTechnologies();
        LoadInstallationTypes();
        LoadProvinces();
        LoadYears();            
    }

    // Note that LoadTechnologies will return as soon as it is
    // called. The part after the await will be scheduled on
    // the UI thread after the task completes with the data
    private async Task LoadTechnologies()
    {
        ddlTechnologies.Datasource = 
            await Task.Run(()=>GizRepository.GetTechnologies());
        ddlTechnologies.DataValueField = "Name";
        ddlTechnologies.DataTextField = "Name";
        ddlTechnologies.Items.Insert(0, new ListItem("All", "-1"));
        ddlTechnologies.DataBind();
    }

    private async Task LoadInstallationTypes()
    {
        ...
    }

    ...
}

Answer 2

目前无法使Simple.Data执行正确的异步数据库调用。工作从下周的第2版开始，第一个要添加的新功能是针对那些后端的正确异步操作 - 例如SQL Server - 其中ADO提供程序具有异步方法。

如何使用Simple.Data异步执行多个DB调用

2 个答案: