Prism RegionAdapter-删除然后添加视图 [英] Prism RegionAdapter - Removing then Adding View

问题描述

我有一个包含AvalonDock的棱镜/wpf/mef解决方案.我创建了一个RegionAdapterBase<Pane>类，该类处理从AvalonDock创建和删除窗格.

I have a prism/wpf/mef solution that contains an AvalonDock. I created a RegionAdapterBase<Pane> class that handles creating and removing the Panes from AvalonDock.

这是我遇到的问题:

1. 我单击菜单中的一个按钮，并且一个视图已注册到一个区域并显示在我的DocumentPane
中
2. 我单击AvalonDock中的关闭按钮以关闭选项卡并删除视图
3. 我单击同一菜单按钮再次将其重新添加
4. 我收到错误:

1. I click a button in my menu and a view is registered with a region and displayed in my DocumentPane
2. I click the close button in AvalonDock to close the tab and remove the view
3. I click the same menu button to add it back again
4. I receive the error:

指定的元素已经是 另一个元素的逻辑子元素. 首先断开连接."

"Specified element is already the logical child of another element. Disconnect it first."

所以...这告诉我需要删除一些东西，但是我无法弄清楚它在哪里.这是我的RegionAdapter中的一些代码:

So... this tells me that something is lingering that I need to remove, but I cannot figure out where it is. Heres some code from my RegionAdapter:

private void OnViewsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e, IRegion region, Pane regionTarget)
{
    if (e.Action == NotifyCollectionChangedAction.Add)
    {
        foreach (object item in e.NewItems)
        {
            UIElement view = item as UIElement;

            if (view is ITabViewInfo)
            {
                if (view != null)
                {
                    DockableContent newContentPane = new DockableContent()
                    {
                        Content = item,
                        Title = ((ITabViewInfo)view).TabViewTitle,
                        Icon = new Image()
                        {
                            Source = new BitmapImage(((ITabViewInfo)view).TabViewIcon)
                        }.Source,
                        IsCloseable = ((ITabViewInfo)view).IsCloseable,
                        HideOnClose = ((ITabViewInfo)view).IsHideOnClose
                    };

                    newContentPane.Closed += (contentPaneSender, args) =>
                    {
                        Debug.WriteLine("Removing view from region", "Prism");
                        region.Remove(item);
                    };

                    regionTarget.Items.Add(newContentPane);
                    newContentPane.Activate();
                }
            }
        }
    } else if (e.Action == NotifyCollectionChangedAction.Remove) {
            regionTarget.Items.Clear();
    }
   }

在我的调试行中，DocumentPane和区域视图已被正确破坏...当我单击将项目添加回视图时，在执行以下操作的行上收到上述错误消息:

From my debug lines, the DocumentPane and region views are properly being destroyed... when I click to add the item back to the view, I get the above error message on the line that does:

Content = item,

这里是按下菜单按钮时运行的模块中的代码:

Heres the code from my module that runs when the menu button is pressed:

    if (_regionManager.Regions["MainRegion"].Views.Any(m => m.GetType() == typeof(Views.ClassicFrontierView)))
    {
        Debug.WriteLine(_regionManager.Regions["MainRegion"].Views.Count());
    }
    else
    {
        Debug.WriteLine("Adding view to region", "Prism");
        _regionManager.RegisterViewWithRegion("MainRegion", typeof(Views.ClassicFrontierView));
    }

知道我缺少什么吗?

推荐答案

我处理Closing事件，而不是处理Closed事件(可能会丢失对基础视图的引用).

Instead of handling the Closed event (which may have lost a reference to the underlying view), I handle the Closing event.

这可行，但是，当我尝试重新打开选项卡时，它显示的是同一实例.阅读此内容后，在复合WPF中 (Prism)，IRegion.Add和IRegionManager.RegisterViewWithRegion有什么区别?我对此进行了更改:

This worked, however, when I tried to re-open the tab, it was displaying the same instance. After reading this In Composite WPF (Prism), what is the difference between IRegion.Add and IRegionManager.RegisterViewWithRegion? I changed this:

_regionManager.RegisterViewWithRegion("MainRegion", typeof(Views.ClassicFrontierView));

对此:

_regionManager.Regions["MainRegion"].Add(new Classic.Views.ClassicFrontierView());

我仍然必须对Prism/avalondock进行一些研究，以确保不会出现内存泄漏，但到目前为止，它似乎仍在工作.

I still have to do some research with Prism / avalondock to make sure there will be no memory leaks, but as of now it appears to be working.

这篇关于Prism RegionAdapter-删除然后添加视图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！