选择 TabItem 时如何更新绑定？ WPF

Question

I had the following code

<mah:MetroWindow x:Class="NeoTec.SprayMachine.WPF.MainWindow"
        namespaces bla bla>

    <Window.Resources>
        <DataTemplate DataType="{x:Type viewModels:CompanyDatabaseViewViewModel}">
            <controls:CompanyDatabaseViewControl/>
        </DataTemplate>

        <DataTemplate DataType="{x:Type viewModels:UserDatabaseViewViewModel}">
            <controls:UserDatabaseViewControl/>
        </DataTemplate>
        
        <DataTemplate DataType="{x:Type viewModels:ParametersViewModel}">
            <controls:ParamatersControl/>
        </DataTemplate>

        <DataTemplate DataType="{x:Type viewModels:SettingsViewModel}">
            <controls:SettingsControl/>
        </DataTemplate>
    </Window.Resources>

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="40"/>
            <RowDefinition/>
        </Grid.RowDefinitions>

        <controls:UpperPanelControl HorizontalAlignment="Center"/>
        <ContentControl Grid.Row="1" Content="{Binding ShownViewModel}"/>
    </Grid>
</mah:MetroWindow>

Where UpperPanelControl is a control with buttons that changes ShownViewModel in MainViewModel . For design purposes I decided to change this all to TabControl (there was a requirement from customer to have buttons):

<mah:MetroWindow x:Class="NeoTec.SprayMachine.WPF.MainWindow"
        namespaces bla bla>
    <TabControl>
        <TabItem Header="Company Database">
            <controls:CompanyDatabaseViewControl DataContext="{Binding CompanyDatabaseViewModel}"/>
        </TabItem>
        <TabItem Header="User Database">
            <controls:UserDatabaseViewControl DataContext="{Binding UserDatabaseViewModel}"/>
        </TabItem>
        <TabItem Header="Parameters" IsSelected="{Binding ParametersTabSelected}">
            <controls:ParamatersControl DataContext="{Binding ParametersViewModel}"/>
        </TabItem>
        <TabItem Header="Settings">
            <controls:SettingsControl DataContext="{Binding SettingsViewModel}"/>
        </TabItem>
        <TabItem Header="Info">
            <controls:InfoControl/>
        </TabItem>
    </TabControl>
</mah:MetroWindow>

It looks nicer, but the problem is when I switch tab the data in the tab is not updated. Are there any chance to get this working with TabControl with updating bindings, when tab is changed?

Answer 1

Each TabItem has an IsSelected property. You can bind that in your View Model and take the appropriate action.

<TabItem Header="Company Database" IsSelected="{Binding CompanyDataBaseTabIsSelected}">
    <controls:CompanyDatabaseViewControl DataContext="{Binding CompanyDatabaseViewModel}"/>
</TabItem>

private bool _companyDatabaseTabIsSelected;
public bool CompanyDatabaseTabIsSelected
{
    get { return _companyDatabaseTabIsSelected; }
    set
    {
        _companyDatabaseTabIsSelected = value;
        _companyDatabaseViewModel.Refresh();
    }
}