绑定TabControl中的SelectedItem [英] Binding SelectedItem in TabControl

问题描述

嗨
这是MVVM项目.我有一个列表框，其中的TabControls位于其中.每个TabControl的TabItem都不相同，并从ViewModel绑定:

Hi
It is MVVM project. I have a ListBox with TabControls inside of it''s items. TabItems are different for each TabControl and are binded from ViewModel:

<tabcontrol itemssource="{Binding Tabs}">
</tabcontrol>

标签为:

Tabs are:

public ObservableCollection<TabItem> Tabs
{   get { return tabs;  }
    set {
        tabs = value;
        value.CollectionChanged += delegate
        {
            OnPropertyChanged("Tabs");
        };

        OnPropertyChanged("Tabs"); } }

标签只能通过以下方式填充一次:

Tabs are filled by the following way only once:

Tabs = new ObservableCollection<tabitem>();

if (details.Image != null || !String.IsNullOrEmpty(details.Summary))
                    Tabs.Add(new TabItem() { Header = "General Info", Content = new GeneralInfo() { DataContext = ItemDetails } });  ........... 6 different types</tabitem>

这是关于我所拥有的一些信息.然后我会动态地更改此TabControls的DataContext，以模拟滚动.

来自ViewModel的所有信息都绑定到控件中，但是TabControl存在问题.标头已绑定.但内容没有.取消选择所有标头，并且TabCntrol内容区域为空.

我试图对SelectedIndex和SelectedItem进行TwoWayBinding，但这没有帮助....似乎SelectedIndex并没有做任何可以选择TabItem的事情.而SelectedItem不起作用，因为我认为在每次更改数据上下文后它都有新的引用.因为TabControl.ItemsSource重新绑定并且创建了新的TabItem.

也许有人解决了相同的问题并知道解决方法?

谢谢

This is a bit info about what I have. Then I dinamically change DataContext''s of this TabControls to simulate scrolling.

All info from ViewModel is binded into control, but there is a problem with TabControl. Headers are binded. but content doesnt. All headers are deselected and TabCntrol content area is empty.

I have tried to make TwoWayBinding on SelectedIndex and SelectedItem, but it doesnt help.... Seems SelectedIndex doesn''t do anything that can select TabItem. And SelectedItem doesn''t work,becuase as I think it has new reference after each changing of data context. Because TabControl.ItemsSource re-binds and new TabItems created.

Maybe someone solved same problem and knows solution?

Thanks

推荐答案

我试图理解您的问题，希望我猜对了.

I tried to understand your problem and, I hope I guessed right.

如果您使用MVVM并更改了DataContext，则您的视图模型可能包含不同的视图模型和更改DataContext的代码.

If you work MVVM and you change DataContext''s, you probably have a view-model that contains the different view-models and the code that changes the DataContext''s.

将SelectedIndex或SelectedItem绑定到当前视图模型无济于事，因为在更改DataContext之后，原始视图模型(绑定到的视图模型)已经消失了

Binding SelectedIndex or SelectedItem to the current view-model doesn''t help since after the DataContext had been changed the original view-model (the view-model that you was bound to) has already gone.

尝试向视图模型添加另一个属性，该属性包含更改DataContext的代码.此属性可以容纳TabControl的SelectedIndex，并且可以在更改DataContext's时使用.

Try to add another property to the view-model that hold the code that changes the DataContext''s. This property can hold the SelectedIndex for the TabControl and, can be used when you change the DataContext''s.

我已经解决了我的问题.
问题是我将控件用作DataContext:
-TabItem列表
-TabItems内容内的控件
有一些过程，我并没有完全理解.但是，想法是，在更改DataContext的同时，可以将一个DataContext分配给2个不同的TabControl.由于UI控件不能同时属于2个父级，因此，应该显示内容中来自DataContext的控件的绑定无效.并且不抛出异常(因为它是绑定的:))

因此，我从DataContext中删除了所有UI对象，并添加了对象模型.并创建显示为这些对象模型的视图的用户控件

I have solved the my issue.
The problem was that I used controls as DataContext:
- List of TabItems
- Controls inside TabItems content
There was some processes, that I dont undrstand entire. But, idea is that while DataContext''s changing, one DataContext can be assigned to 2 different TabControls. Since UI Controls cant belong to 2 parents at the same moment, so, binding that should show that controls from DataContext in content doesnt work. And doesnt throw excpetion (cause it''s binding :) )

So, I remove al UI objects from DataContext, and add object models. And create UserControls that display are Views for these object models

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