Xamly determine if a ListBox.Items.Count > 0

Question

Is there a way in XAML to determine if the ListBox has data?

I wanna set its IsVisibile property to false if no data.

Answer 1

You can probably make this work using a ValueConverter and normal binding.

Set Visibility to be:

Visibility = "{Binding myListbox.Items.Count, Converter={StaticResource VisibilityConverter}}"

Then set up your converter to return Visibility.Collapsed etc based on the value of the count.

Answer 2

Do it in a trigger and you won't need a ValueConverter:

<ListBox>
    <ListBox.Style>
        <Style TargetType="{x:Type ListBox}">
            <Setter Property="Visibility" Value="Visible" />

            <Style.Triggers>
                <DataTrigger Binding="Items.Count,{Binding RelativeSource={RelativeSource Self}}" Value="0">
                    <Setter Property="Visibility" Value="Hidden" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ListBox.Style>
</ListBox>

So that shows the ListBox by default, but if Items.Count is ever 0, the ListBox is hidden.

Answer 3

The ListBox contains a HasItems property you can bind to. So you can just do this:

<BooleanToVisibilityConverter x:Key="BooleanToVisibility" />
...
<ListBox Visibility="{Binding HasItems, RelativeSource={RelativeSource Self}, Converter=BooleanToVisibility}" ... />

Or as a Trigger so you don't need the converter:

<ListBox>
    <ListBox.Style>
        <Style TargetType="{x:Type ListBox}">
            <Setter Property="Visibility" Value="Visible" />

            <Style.Triggers>
                <DataTrigger Binding="{Binding HasItems, RelativeSource={RelativeSource Self}}" Value="False">
                    <Setter Property="Visibility" Value="Hidden" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </ListBox.Style>
</ListBox>

I haven't tested the bindings so there might be some typos but you should get the idea.