如何使用数据模板处理多个选项卡的已启用属性? [英] How to handle enabled property of multiple tabs using Data Templates?

问题描述

我有一个带有两个选项卡的窗口，其中包含两个不同的用户控件.为了启用/禁用导航到第二个选项卡，我从IPageViewModel界面在两个VM中实现了一个IsEnabled属性.

I have a Window with two tabs, that holds two different user controls. In order to enable/disable navigation to the second tab, I implement an IsEnabled property in both VM's from the IPageViewModel interface.

当通过CustomerDetailsViewModel的Messenger服务在CustomerOrdersViewModel中接收到SelectedCustomer时，IsEnabled布尔值属性设置为true.

The IsEnabled boolean property is set to true when a SelectedCustomer is received in the CustomerOrdersViewModel, via Messenger service from CustomerDetailsViewModel.

到目前为止，此方法有效，因为当我从第一个视图的数据网格中选择一个客户时，第二个选项卡已启用.但是问题是当我尝试选择第一个选项卡以返回初始视图时，它被禁用.

So far this method works, as the second tab is enabled when I select a customer from the data grid in the first view. But the problem is when I try to select the first tab to go back to the initial view, it is disabled.

这是特定导航问题的屏幕截图.

This is a screen cast of the specific navigation issue.

我不确定为什么使用信使将IsEnabled属性设置为true时，两个选项卡都将启用.

I'm not sure why as I thought when I set the IsEnabled property to true using the messenger, both tabs would be enabled.

有人在此问题上有任何建议吗?

Does anyone have any advice on the issue here?

在CustomerDetailsViewModel中，我通过Messenger发送selectedCustomer:

In the CustomerDetailsViewModel I send the selectedCustomer via a messenger:

    private CustomerModel selectedCustomer;
    public CustomerModel SelectedCustomer
    {
        get
        {
            return selectedCustomer;
        }
        set
        {
            selectedCustomer = value;
            Messenger.Default.Send<CustomerModel>(selectedCustomer);
            RaisePropertyChanged("SelectedCustomer");
        }
    }

然后在CustomerDetailsViewModel中将IsEnabled属性设置为true，因为已传递SelectedCustomer:

Then in the CustomerDetailsViewModel the IsEnabled property is set to true as the SelectedCustomer has been passed over:

    public CustomerOrdersViewModel()
    {


        Messenger.Default.Register<CustomerModel>(this, OnCustomerReceived);


    }


    public void OnCustomerReceived(CustomerModel customer)
    {
        SelectedCustomer = customer;
        IsEnabled = true;
    }

这是既包含用户控件又包含为每个控件生成的选项卡的ApplicationView xaml:

This is the ApplicationView xaml that holds both user controls, and the tabs generated for each:

<Window x:Class="MongoDBApp.Views.ApplicationView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:views="clr-namespace:MongoDBApp.Views"
        xmlns:vm="clr-namespace:MongoDBApp.ViewModels"
        Title="ApplicationView"
        Width="800"
        Height="500">

    <Window.Resources>
        <DataTemplate DataType="{x:Type vm:CustomerDetailsViewModel}">
            <views:CustomerDetailsView />
        </DataTemplate>
        <DataTemplate DataType="{x:Type vm:CustomerOrdersViewModel}">
            <views:CustomerOrdersView />
        </DataTemplate>
    </Window.Resources>

    <Window.DataContext>
        <vm:ApplicationViewModel />
    </Window.DataContext>


    <TabControl ItemsSource="{Binding PageViewModels}"
                SelectedItem="{Binding CurrentPageViewModel}"
                TabStripPlacement="Top">
        <TabControl.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding Name}" />
            </DataTemplate>
        </TabControl.ItemTemplate>
        <TabControl.ItemContainerStyle>
            <Style TargetType="{x:Type TabItem}">
                <Setter Property="IsEnabled" Value="{Binding IsEnabled}"/>
            </Style>
        </TabControl.ItemContainerStyle>
    </TabControl>
</Window>

推荐答案

为什么不只是将CustomerDetailsViewModel的IsEnabled属性默认为true?

Why not just default the IsEnabled property of the CustomerDetailsViewModel to true?

该标签应始终启用，这样对我来说最有意义.

It's a tab that should always be enabled, so that would make the most sense to me.

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