我有一个 Image 控件，它的源绑定到对象上的属性（字符串 url 到图像）。进行服务调用后，我使用新 URL 更新数据对象。在调用 PropertyChanged 事件后，它离开我的代码后引发异常。
数据结构和服务逻辑都在一个不了解 UI 的核心 dll 中完成。当我无法访问 Dispatcher 时，如何与 UI 线程同步？
PS：访问 Application.Current.RootVisual 以获取 Dispatcher 不是解决方案，因为根视觉对象位于不同的线程上（导致我需要防止的确切异常）。
PPS：这只是图像控件的问题，绑定到任何其他 ui 元素，为您处理跨线程问题。
System.Windows.Deployment.Current.Dispatcher.BeginInvoke(() => {...});
也看这里。
您是否尝试过实施INotifyPropertyChanged？
我遇到了与此类似的问题，但这是在 Windows 窗体中：
我有一个类，它有自己的线程，更新另一个进程的统计信息，我的 UI 中有一个控件数据绑定到这个对象。我遇到了跨线程调用问题，这是我解决它的方法：
Form m_MainWindow; //Reference to the main window of my application
protected virtual void OnPropertyChanged(string propertyName)
{
if(PropertyChanged != null)
if(m_MainWindow.InvokeRequired)
m_MainWindow.Invoke(
PropertyChanged, this, new PropertyChangedEventArgs(propertyName);
else
PropertyChanged(this, new PropertyChangedEventArgs(propertyName);
}
这似乎工作得很好，如果有人有建议，请告诉我。
Application 类上 RootVisual 的属性 getter 具有导致该异常的线程检查。我通过将根视觉对象的调度程序存储在我自己的 App.xaml.cs 中的属性中解决了这个问题：
public static Dispatcher RootVisualDispatcher { get; set; }
private void Application_Startup(object sender, StartupEventArgs e)
{
this.RootVisual = new Page();
RootVisualDispatcher = RootVisual.Dispatcher;
}
如果您随后在 App.RootVisualDispatcher 而不是 Application.Current.RootVisual.Dispatcher 上调用 BeginInvoke，则不应出现此异常。
当我们想要更新应该在 UI 线程中发生的操作的 UI 相关项时，您将得到一个无效的跨线程访问异常
Deployment.Current.Dispatcher.BeginInvoke( () =>
{
UpdateUI(); // DO the actions in the function Update UI
});
public void UpdateUI()
{
//to do :Update UI elements here
}
该INotifyPropertyChanged接口用于通知客户端（通常是绑定客户端）属性值已更改。
例如，考虑一个具有名为 FirstName 的属性的 Person 对象。为了提供通用属性更改通知，Person 类型实现了 INotifyPropertyChanged 接口，并在 FirstName 更改时引发 PropertyChanged 事件。
要在绑定客户端和数据源之间的绑定中发生更改通知，您的绑定类型应该：
实现INotifyPropertyChanged接口（首选）。
为绑定类型的每个属性提供一个更改事件。
不要两者都做。
例子：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Runtime.CompilerServices;
using System.Windows.Forms;
// Change the namespace to the project name.
namespace TestNotifyPropertyChangedCS
{
// This form demonstrates using a BindingSource to bind
// a list to a DataGridView control. The list does not
// raise change notifications. However the DemoCustomer type
// in the list does.
public partial class Form1 : Form
{
// This button causes the value of a list element to be changed.
private Button changeItemBtn = new Button();
// This DataGridView control displays the contents of the list.
private DataGridView customersDataGridView = new DataGridView();
// This BindingSource binds the list to the DataGridView control.
private BindingSource customersBindingSource = new BindingSource();
public Form1()
{
InitializeComponent();
// Set up the "Change Item" button.
this.changeItemBtn.Text = "Change Item";
this.changeItemBtn.Dock = DockStyle.Bottom;
this.changeItemBtn.Click +=
new EventHandler(changeItemBtn_Click);
this.Controls.Add(this.changeItemBtn);
// Set up the DataGridView.
customersDataGridView.Dock = DockStyle.Top;
this.Controls.Add(customersDataGridView);
this.Size = new Size(400, 200);
}
private void Form1_Load(object sender, EventArgs e)
{
// Create and populate the list of DemoCustomer objects
// which will supply data to the DataGridView.
BindingList<DemoCustomer> customerList = new BindingList<DemoCustomer>();
customerList.Add(DemoCustomer.CreateNewCustomer());
customerList.Add(DemoCustomer.CreateNewCustomer());
customerList.Add(DemoCustomer.CreateNewCustomer());
// Bind the list to the BindingSource.
this.customersBindingSource.DataSource = customerList;
// Attach the BindingSource to the DataGridView.
this.customersDataGridView.DataSource =
this.customersBindingSource;
}
// Change the value of the CompanyName property for the first
// item in the list when the "Change Item" button is clicked.
void changeItemBtn_Click(object sender, EventArgs e)
{
// Get a reference to the list from the BindingSource.
BindingList<DemoCustomer> customerList =
this.customersBindingSource.DataSource as BindingList<DemoCustomer>;
// Change the value of the CompanyName property for the
// first item in the list.
customerList[0].CustomerName = "Tailspin Toys";
customerList[0].PhoneNumber = "(708)555-0150";
}
}
// This is a simple customer class that
// implements the IPropertyChange interface.
public class DemoCustomer : INotifyPropertyChanged
{
// These fields hold the values for the public properties.
private Guid idValue = Guid.NewGuid();
private string customerNameValue = String.Empty;
private string phoneNumberValue = String.Empty;
public event PropertyChangedEventHandler PropertyChanged;
// This method is called by the Set accessor of each property.
// The CallerMemberName attribute that is applied to the optional propertyName
// parameter causes the property name of the caller to be substituted as an argument.
private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
// The constructor is private to enforce the factory pattern.
private DemoCustomer()
{
customerNameValue = "Customer";
phoneNumberValue = "(312)555-0100";
}
// This is the public factory method.
public static DemoCustomer CreateNewCustomer()
{
return new DemoCustomer();
}
// This property represents an ID, suitable
// for use as a primary key in a database.
public Guid ID
{
get
{
return this.idValue;
}
}
public string CustomerName
{
get
{
return this.customerNameValue;
}
set
{
if (value != this.customerNameValue)
{
this.customerNameValue = value;
NotifyPropertyChanged();
}
}
}
public string PhoneNumber
{
get
{
return this.phoneNumberValue;
}
set
{
if (value != this.phoneNumberValue)
{
this.phoneNumberValue = value;
NotifyPropertyChanged();
}
}
}
}
}