Alex Krass's questions

在工作室中打开 CSS 文件时，出现组件错误，编辑器敲掉标记。

ActivityLog.xml 日志文件包含以下信息。

  <entry>
    <record>746</record>
    <time>2017/11/17 18:49:57.319</time>
    <type>Error</type>
    <source>Editor or Editor Extension</source>
    <description>
        System.ArgumentNullException: Value cannot be null.
        Parameter name: value
        at System.Enum.ToObject(Type enumType, Object value)
        at Microsoft.VisualStudio.Shell.DialogPage.SetPropertyValue(PropertyDescriptor descriptor, Object automationObject, Object value)
        at Microsoft.VisualStudio.Shell.DialogPage.LoadSettingFromStorage(PropertyDescriptor prop)
        at Microsoft.VisualStudio.Shell.DialogPage.LoadSettingsFromStorage()
        at Microsoft.VisualStudio.Shell.DialogPage.set_Site(ISite value)
        at System.ComponentModel.Container.Add(IComponent component, String name)
        at System.ComponentModel.Container.Add(IComponent component)
        at Microsoft.VisualStudio.Shell.Package.GetDialogPage(Type dialogPageType)
        at Microsoft.VisualStudio.Html.Package.Package.CSS.CssPackage.GetAutomationObject(String name)
        at Microsoft.VisualStudio.Shell.Package.Microsoft.VisualStudio.Shell.Interop.IVsPackage.GetAutomationObject(String propName, Object&amp; auto)
        at Microsoft.VisualStudio.Web.Editor.Package.Settings.Common.WebSettingsStorageWithDialog.LoadFromStorage()
        at Microsoft.Web.Editor.Host.WebEditor.GetSettings(String contentTypeName)
        at Microsoft.CSS.Editor.Settings.CssSettings.get_Storage()         
        at Microsoft.CSS.Editor.Settings.CssSettings.get_ValidationEnabled()
        at Microsoft.CSS.Editor.Checker.CssErrorTagger..ctor(ITextBuffer textBuffer)
        at Microsoft.CSS.Editor.Checker.CssErrorTagger.Attach(ITextBuffer textBuffer)
        at Microsoft.CSS.Editor.Checker.CssErrorTaggerProvider.CreateTagger[T](ITextBuffer textBuffer)
        at Microsoft.VisualStudio.Text.Tagging.Implementation.TagAggregator`1.GatherTaggers(ITextBuffer textBuffer)
        --- End of stack trace from previous location where exception was thrown ---   
        at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
    </description>
  </entry>

好吧，编辑器页面显示错误。

我尝试禁用和启用组件以使用 ASP.NET，包括 CSS 组件，但没有成功。试图恢复，再次没有。任何想法如何解决这一问题？

有一个查询最多可能需要一个小时才能完成。为了不阻塞用户界面，它通过任务。如果用户厌倦了等待，这个请求应该被取消。如何正确地做到这一点，以便连接不会在加载数据库时挂起一个小时，并且用户不会创建一堆它们？也许除了任务之外还有其他选择？

private void UpdateGrid(){
    SomeRows rows;
    Task task = new Task(() => 
    {
        rows = IDBConnectInstance.SelectRows();
    });
    task.ContinueWith(() =>
    {
        dataGridView.DataSource = rows;
    }, TaskScheduler.FromCurrentSynchronizationContext());
}

更新：

没有额外加的点，IDBConnectInstance本身就是一个来自第三方库的接口。即进入库函数IDBConnectInstance.SelectRows，停止等待完成。如果可以处理CancellationToken，问题就不会出现了。

IDBConnect
{
    SelectRows();
}

public class DBConnect: IDBConnect
{
    public List<SomeClass> SelectRows()
    {
        String query = "Очень долгий SELECT из БД";
        List<SomeClass> result = new List<SomeClass>();
        using(OracleConnection dbconn = new OracleConnection(ConnectionString))
        {
            dbconn.Open();

            OracleCommand command = new OracleCommand(query, dbconn);
            OracleDataReader reader = command.ExecuteReader();
            while (reader.Read())
            {
                SomeClass someClass = new someClass()
                {
                    SomeField = reader[0],
                    SomeField = reader[1],
                    ...
                }
                result.Add(someClass);
            }
            reader.Close();
            dbconn.Close();
        }
        return result;
    }
}

到目前为止，只有一个想法返回Thread并使用已弃用的Thread.Abort();

我试图弄清楚如何改进 WinForms 体验以及分离逻辑和表示。我遇到了一个带有简短示例的 MVP 模板，并试图弄清楚如何使用它。目前我有以下代码，但我认为我做错了什么。此外，多线程的实现根本不适合这个模型。因此问题是，如何在 WinForms 中正确实施 MVP 设计模式？

查看实现

interface ICustomer
{
    string FirstName { get; set; }
    string LastName { get; set; }
    string SurName { get; set; }
    string Address { get; set; }
    string Code { get; set; }

    event Action Search;
    event Action Cancel;
}

public partial class Customer : Form, ICustomer
{
    public string FirstName
    {
        get { return lblFirstName.Text; }
        set { lblFirstName.Text = value; }
    }

    public string LastName
    {
        get { return lblLastName.Text; }
        set { lblLastName.Text = value; }
    }

    public string SurName
    {
        get { return lblSurname.Text; }
        set { lblSurname.Text = value; }
    }

    public string Address
    {
        get { return lblAddress.Text; }
        set { lblAddress.Text = value; }
    }

    public string Code
    {
        get { return txtCode.Text; }
        set { txtCode.Text = value; }
    }

    public event Action Search;
    public event Action Cancel;

    public Customer()
    {
        InitializeComponent();
    }

    private void btnSearch_Click(object sender, EventArgs e)
    {
        Search();
    }

    private void btnCancel_Click(object sender, EventArgs e)
    {
        Cancel();
    }
}

演示器实现

class CustomerPresenter 
{
    public ICustomer View;
    public ICustomerModel Model;

    public CustomerPresenter(ICustomer view, ICustomerModel model)
    {
        View = view;
        Model = model;

        View.Search += View_Search;
        View.Cancel += View_Cancel;
    }

    private void View_Search()
    {
        new Task(() => {
            View.FirstName = "Alex Krass";
        }).Start();
    }

    private void View_Cancel()
    {

    }
}

模式与挑战

我的模型还是空的，按照我的理解，应该没有问题，通过Unity IoC调用所有这些耻辱。

class UnityIoC
{
    private static UnityContainer unityContainer;

    public static UnityContainer Instance 
    {
        get
        {
            if (unityContainer == null) CreateContainer();
            return unityContainer;
        }
    }

    private static void CreateContainer()
    {
        unityContainer = new UnityContainer();
        unityContainer.RegisterType<ICustomer, Customer>();
        unityContainer.RegisterType<ICustomerModel, CustomerModel>();
    }
} 

static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);

    ApplicationContext context = new ApplicationContext()
    {
        MainForm = UnityIoC.Instance.Resolve<CustomerPresenter>().View as Form
    };
    context.MainForm.Show();

    Application.Run(context);
}

那么，相应地，当我单击“搜索”按钮时，我无法更新 UI，我真的必须将 TextBox 本身转发给 Presenter 中的 ICustomer 并调用 BeginInvoke 吗？或者我只是误解了 MVP 的实施？

更新：

在不阻塞的情况下更新 UI 的问题似乎已经通过使用计时器解决了，当信息需要在完成时Task和之后TaskScheduler，当它需要在完成后更新时Task。

**Вариант 1**

timer = new Timer() { Interval = 1000 };
timer.Tick += timer_Tick;
timer.Start();

private void timer_Tick(object sender, EventArgs e)
{
    UpdateView();
}

**Вариант 2**
task = new Task(new Action(UpdateModel));
task.ContinueWith(new Action<Task>(UpdateView), TaskScheduler.FromCurrentSynchronizationContext());
task.Start();


private void UpdateView(Task task = null)
{
    view.SomeVal = SomeVal;
    view.SomeValNext = SomeValNext;
}