棱镜4 - 局部范围的RegionManager

Question

我有使用PRISM 4的silverlight 4应用程序,我正在使用MEF.

我的Shell定义了一个加载模块的主要区域,我希望模块有自己的RegionManager,因此它们定义的区域是本地RegionManager而不是global的位置.并且我想在模块内部通过容器(对于类型IRegionManager)解析此本地RegionManager.

但是来自文档的方法:

IRegion detailsRegion = this.regionManager.Regions["DetailsRegion"];
View view = new View();
bool createRegionManagerScope = true;
IRegionManager detailsRegionManager = detailsRegion.Add(view, null, 
                            createRegionManagerScope);

对我来说不起作用,当从子视图中解析IRegionManager时,我仍然得到GlobalRegionManager.

Answer 1

我遇到了与你相同的情况,我有一个嵌套的区域经理,但所有的子视图仍然是全球区域经理.我提出了我认为合理的解决方案.

首先我定义一个接口:

/// <summary>
/// An interface which is aware of the current region manager.
/// </summary>
public interface IRegionManagerAware
{
    /// <summary>
    /// Gets or sets the current region manager.
    /// </summary>
    /// <value>
    /// The current region manager.
    /// </value>
    IRegionManager RegionManager { get; set; }
}

然后我设置RegionBehavior如下:

/// <summary>
/// A behaviour class which attaches the current scoped <see cref="IRegionManager"/> to views and their data contexts.
/// </summary>
public class RegionAwareBehaviour : RegionBehavior
{
    /// <summary>
    /// The key to identify this behaviour.
    /// </summary>
    public const string RegionAwareBehaviourKey = "RegionAwareBehaviour";

    /// <summary>
    /// Override this method to perform the logic after the behaviour has been attached.
    /// </summary>
    protected override void OnAttach()
    {
        Region.Views.CollectionChanged += RegionViewsChanged;
    }

    private void RegionViewsChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        Contract.Requires<ArgumentNullException>(e != null);

        if (e.NewItems != null)
            foreach (var item in e.NewItems)
                MakeViewAware(item);
    }

    private void MakeViewAware(object view)
    {
        Contract.Requires<ArgumentNullException>(view != null);

        var frameworkElement = view as FrameworkElement;
        if (frameworkElement != null)
            MakeDataContextAware(frameworkElement);

        MakeAware(view);
    }

    private void MakeDataContextAware(FrameworkElement frameworkElement)
    {
        Contract.Requires<ArgumentNullException>(frameworkElement != null);

        if (frameworkElement.DataContext != null)
            MakeAware(frameworkElement.DataContext);
    }

    private void MakeAware(object target)
    {
        Contract.Requires<ArgumentNullException>(target != null);

        var scope = target as IRegionManagerAware;
        if (scope != null)
            scope.RegionManager = Region.RegionManager;
    }
}

然后将其应用于引导程序中的所有区域:

protected override IRegionBehaviorFactory ConfigureDefaultRegionBehaviors()
{
    var behaviours = base.ConfigureDefaultRegionBehaviors();

    behaviours.AddIfMissing(RegionAwareBehaviour.RegionAwareBehaviourKey, typeof(RegionAwareBehaviour));

    return behaviours;
}

然后你所要做的就是IRegionManagerAware在你的view/viewmodel上实现,可能是这样的:

public class MyView : IRegionManagerAware
{
    IRegionManager RegionManager { set; get; }
}

然后,当此视图添加到区域时,该行为将正确地将该RegionManager属性设置为当前作用域区域管理器.