XAML custom text in TextBlock - wpf

Question

Good afternoon,
I´m binding a list of doubles (Latlng) to an ItemsControl and in a TextBlock I want to make a custom text when the list binded has a count of 0. With the code I have the TextBlock is empty when the ItemsSource of the ItemsControl is that list.
What am I doing wrong?
Btw the list Latlng is a property of a class.
<ItemsControl Name="icLatLng" ItemsSource="{Binding Latlng}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock FontFamily="Arial" FontSize="14">
<TextBlock.Style>
<Style>
<Setter Property="TextBlock.Text" Value="{Binding}"></Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource AncestorType=ItemsControl}, Path=Items.Count}" Value="0">
<Setter Property="TextBlock.Text" Value="—"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Thanks in advance.

Answer 1

Welcome to SO.
ItemsControl.ItemTemplate is the template that gets applied to each element in the Items list the control is bound to. If there are no items to begin with, then it won't be created, so anything you do in it won't be seen.
I suspect what you're really trying to do is replace the look of the entire control when the list is empty. If so, you can do that by applying a new template to the ItemsControl itself using a DataTrigger on the HasItems property:
<ItemsControl Name="icLatLng" ItemsSource="{Binding Latlng}">
<ItemsControl.Style>
<Style TargetType="{x:Type ItemsControl}" BasedOn="{StaticResource {x:Type ItemsControl}}">
<Style.Triggers>
<DataTrigger Binding="{Binding HasItems, RelativeSource={RelativeSource Self}}" Value="False">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ItemsControl}">
<TextBlock Text="-" />
</ControlTemplate>
</Setter.Value>
</Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</ItemsControl.Style>
</ItemsControl>