标签:
为了解决NotifyPorpertyChanged的线程与界面绑定异步更新冲突问题,所以查看相关资料后,将自己的NotifyPropertyChanged作了改进。
1.问题起因
在开发C#应用程序,通常后使用到界面控件特定属性(Enable | Text)与指定的类成员绑定。但如果指定类成员变量在线程中和界面需异步更新时,会出现异常情况(界面显示异常)。
以下代码未作异步更新,示例如下:
public class TubeConsumedRecord : INotifyPropertyChanged
{
/// <summary>
/// The lock tube
/// </summary>
private object lockTube;
/// <summary>
/// The available count
/// </summary>
private int availableCount;
/// <summary>
/// 在属性值更改时发生。
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Gets or sets the available tube count.
/// </summary>
/// <value>The available tube count.</value>
public int AvailableTubeCount
{
get
{
return availableCount;
}
set
{
if (this.availableCount == value)
{
return;
}
this.availableCount = value;
OnPropertyChanged(new PropertyChangedEventArgs("AvailableTubeCount"));
}
}
/// <summary>
/// Handles the <see cref="E:PropertyChanged" /> event.
/// </summary>
/// <param name="e">The <see cref="PropertyChangedEventArgs"/> instance containing the event data.</param>
private void OnPropertyChanged(PropertyChangedEventArgs e)
{
if (PropertyChanged != null)
PropertyChanged(this, e);
}
/// <summary>
/// Initializes a new instance of the <see cref="TubeConsumedRecord"/> class.
/// </summary>
public TubeConsumedRecord()
{
this.lockTube = new object();
}
}
2. 解决方法
为了解决属性绑定的界面和线程异步更新时冲突问题,对INotifyPropertyChanged作了相应的改造。
改造后的类AsynNotifyPropertyChanged, 直接继承使用。
设置异步上下文类为SynchronizationContextProvider,需要用户设置界面的异步上下文,在创造主窗体Main()中添加。
SynchronizationContextProvider.CreateSynchronizationContext(WindowsFormsSynchronizationContext.Current);
AsynNotifyPropertyChanged代码如下:
public class AsynNotifyPropertyChanged : INotifyPropertyChanged
{
/// <summary>
/// Initializes a new instance of the <see cref="AsyncBindingData"/> class.
/// </summary>
public AsynNotifyPropertyChanged()
{
}
/// <summary>
/// Occurs when a property value changes.
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Called when [property changed].
/// </summary>
/// <param name="propertyName">Name of the property.</param>
public void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged == null||string.IsNullOrEmpty(propertyName))
{
return;
}
if (SynchronizationContextProvider.UISynchronizationContext != null)
{
SynchronizationContextProvider.UISynchronizationContext.Send(new SendOrPostCallback(AysnPropertyChanged), propertyName);
}
else
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
private void AysnPropertyChanged(object state)
{
string propertyName = state.ToString();
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
public void OnPropertyChanged(object sender, PropertyChangedEventHandler propertyChanged, string propertyName)
{
if (propertyChanged == null || string.IsNullOrEmpty(propertyName))
{
return;
}
if (SynchronizationContextProvider.UISynchronizationContext != null)
{
SynchronizationContextProvider.UISynchronizationContext.Send(new SendOrPostCallback(AysnPropertyChanged), propertyName);
}
else
{
propertyChanged(sender, new PropertyChangedEventArgs(propertyName));
}
}
}
SynchronizationContextProvider类代码如下:
public class SynchronizationContextProvider
{
/// <summary>
/// The current
/// </summary>
private static SynchronizationContext current;
/// <summary>
/// Gets the UI synchronization context.
/// </summary>
/// <value>The UI synchronization context.</value>
internal static SynchronizationContext UISynchronizationContext
{
get
{
if(SynchronizationContext.Current==null)
{
SynchronizationContext.SetSynchronizationContext(current);
}
return current;
}
}
/// <summary>
/// Creates the synchronization context.
/// </summary>
/// <param name="context">The context.</param>
public static void CreateSynchronizationContext(SynchronizationContext context)
{
current = context;
}
}
标签: 来源: https://blog.csdn.net/zhengxu25689/article/details/82877545
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