WPF线程：我可以更新非UI线程中的控件的数据上下文吗？ [英] WPF threading: can I update a control's data context in a non-UI thread?

问题描述

我们可以更新WPF控件在一个非UI线程的数据上下文？

Can we update the data context of a WPF control in a non-UI thread?

假设我们有一个标签有 MyClass的作为数据上下文，并绑定内容到 myProperty的：

Say we have a Label that has MyClass as data context, and bind Content to MyProperty:

<标签名称=标签CONTENT ={结合myProperty的}/> ，

其中， MyClass的很简单：

public class MyClass : INotifyPropertyChanged
{
    int _myField;
    public int MyProperty
    {
        get
        {
            return _myField;
        }
        set
        {
            _myField = value;
            PropertyChanged(this, new PropertyChangedEventArgs("MyProperty"));
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;
}

在一个非UI线程，我们可以做 myClass.MyProperty =更新来更新标签的内容，但我们不能 label.Content =更新直接做。那是正确的。

In a non-UI thread, we can do myClass.MyProperty = "updated" to update the content of the label, but we cannot do label.Content = "updated" directly. Is that correct?

我自己的答案：

下面就是我发现：

• 从一个非UI线程，您不能更新控制;


• 从一个非UI线程，您可以控件的数据上下文的更新属性;


• 从一个非UI线程，您不能添加项目或删除从项目 ObserverableCollection 绑定到一个控制。但是有一个解决方法： http://geekswithblogs.net/NewThingsILearned/archive/2008/01/16/have-worker-thread-update-observablecollection-that-is-bound-to- a.aspx

• From a non-UI thread, you cannot update a control;
• From a non-UI thread, you can update properties of a control's data context;
• From a non-UI thread, you cannot add items to or remove items from an ObserverableCollection that is bound to a control. But there is a workaround: http://geekswithblogs.net/NewThingsILearned/archive/2008/01/16/have-worker-thread-update-observablecollection-that-is-bound-to-a.aspx

推荐答案

是啊，这是正确的。没有与集合，以及（在 CollectionChanged 事件具有在UI线程中执行）的其他注意事项。

Yup, that is correct. There are additional caveats with collections as well (The CollectionChanged event has to be executed in the UI thread).

通常情况下，你使用的ObservableCollection< T> 用于绑定到集合。如果从非UI线程更新此集合，代码将打破，因为事件是由他们的意见（执行相同的线程中触发的ObservableCollection< T> 触发一个事件当集合中的改变发生）。为了克服这一点，你必须委托供给的自定义实现的ObservableCollection< T> 这触发在UI线程事件（使用分派器）

Usually, you are using ObservableCollection<T> for binding to a collection. If you update this collection from a non-UI thread, the code will break, as events are fired from the same thread they are executed on (ObservableCollection<T> fires an event when changes in the collection happen). To circumvent this, you have to supply a delegate to a custom implementation of ObservableCollection<T> which fires the event in the UI thread (using the Dispatcher).

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