TabItem and TabContent template changing based on properties value

Question

I have a TabControl item in WPF .Net with 2 templates for content and 2 templates for tabitems. I bind my own objects as ItemsSource, which has two properties:

public bool IsPrivMsgChannel
{
    get
    {
        return _IsPrivMsgChannel;
    }
    set
    {
        _IsPrivMsgChannel = value;
        if (_IsPrivMsgChannel)
        {
            Joined = true;
        }
    }
}

And

public bool Joined
{ 
    get
    {
        return _Joined;
    }
    set
    {
        _Joined = value;
        // Notify the UI thread!
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs("Joined"));
    }
}

The first property will be set when the object is initialized, it won't change. The second property may change, and it sends a notification then to the UI.

I would like to change the TabItem template of my TabContol based on the IsPrivMsgChannel property, and the TabContent template based on the Joined property.

---

UPDATE My solution is looks like this right now:

<TabControl x:Name="Channels" Grid.Column="0" Grid.Row="1" TabStripPlacement="Left" SelectionChanged="ChannelChanged" ContentTemplateSelector="{StaticResource MyContentTemplateSelector}" ItemTemplateSelector="{StaticResource MyItemTemplateSelector}">
<TabControl.Resources>
    <DataTemplate x:Key="TabItemChannelTemplate">
        <Label HorizontalAlignment="Center" VerticalAlignment="Center" Content="{Binding Name}"></Label>
    </DataTemplate>
    <DataTemplate x:Key="TabItemPrivChatTemplate">
        <Label HorizontalAlignment="Center" VerticalAlignment="Center" Content="Private"></Label>
    </DataTemplate>

    <DataTemplate x:Key="TabContentDisconnected">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="40"></RowDefinition>
                <RowDefinition Height="40"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
            </Grid.RowDefinitions>

            <Label Grid.Column="0" Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Center" Content="{Binding Description}"></Label>
            <Button Grid.Column="0" Grid.Row="1" Width="100" Content="Enter this channel" Click="Enter_Channel"></Button>
        </Grid>
    </DataTemplate>
    <DataTemplate x:Key="TabContentConnected">
        <Grid>
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition Height="40"></RowDefinition>
                <RowDefinition Height="40"></RowDefinition>
                <RowDefinition Height="*"></RowDefinition>
            </Grid.RowDefinitions>

            <Label Grid.Column="0" Grid.Row="0" HorizontalAlignment="Center" VerticalAlignment="Center" Content="{Binding Description}"></Label>
            <Button Grid.Column="0" Grid.Row="1" Width="100" Content="Leave this channel" Click="Leave_Channel"></Button>
            <DockPanel Grid.Column="0" Grid.Row="2">
                <ListBox x:Name="GameList" HorizontalContentAlignment="Stretch" ItemTemplate="{DynamicResource GameListTemplate}" ItemsSource="{Binding GameList}" Visibility="{Binding CanHost, Converter={StaticResource BoolToVisibilityConverter}}" DockPanel.Dock="Top" Height="250" SelectionChanged="GameListSelectionChanged"></ListBox>
                <ScrollViewer VerticalScrollBarVisibility="Auto" ScrollChanged="MessageScrollChanged" DockPanel.Dock="Bottom">
                    <TextBox x:Name="Messages" Text="{Binding Messages}" TextWrapping="Wrap"></TextBox>
                </ScrollViewer>
            </DockPanel>
        </Grid>
    </DataTemplate>
    <Style TargetType="{x:Type TabItem}">
        <Style.Triggers>
            <DataTrigger Binding="{Binding Joined}" Value="True">
                <Setter Property="ContentTemplate" Value="{StaticResource TabContentConnected}"></Setter>
            </DataTrigger>
        </Style.Triggers>
    </Style>
</TabControl.Resources>
</TabControl>

So I made two DataTemplateSelector class. One will select the template for the Items and one will select the template for the Content.

But since Joined property can change I must create Style.Triggers to handle if that property changes and change the ContentTemplate if needed.

The only thing I can't understand is why triggers work only with TargetType TabItem of the Style and not with TargetType TabControl.

Answer 1

Sounds to me like you want to use a DataTemplateSelector. There's an example of using it here: http://tech.pro/tutorial/807/wpf-tutorial-how-to-use-a-datatemplateselector

Basically, you implement a DataTemplateSelector where the SelectTemplate method selects which template to use based on the container and the item, create an instance of it in your XAML then assign it to a ItemTemplateSelector attribute on an items control.

Answer 2

Modify the Data Triggers as given below.

   <DataTrigger Binding="{Binding Path=DataContext.Joined,RelativeSource={RelativeSource Self}}" Value="True">
     <Setter Property="ContentTemplate" Value="{DynamicResource TabContentConnected}" />
   </DataTrigger>
   <DataTrigger Binding="{Binding Path=DataContext.IsPrivMsgChannel,RelativeSource={RelativeSource Self}}" Value="True">
     <Setter Property="ItemTemplate" Value="{DynamicResource TabItemTemplate2}" />
   </DataTrigger>