CODEWITHSUNDEEP
wpftriggersdatatriggerwpf-style
Serge P.
Serge P.

Reputation: 327

Hide whole Expander if header is empty

I have an Expander WPF control which header's template is a simple TextBlock. I want to hide whole expander if TextBlock.Text (which is filled dynamically from outside) is null or empty.

<Expander>
    <Expander.Header>
        <TextBlock Text="{Binding Path=Name}"/>
    </Expander.Header>
</Expander>

Upvotes: 1

Views: 2647

Answers (2)

Smirnov Denis
Smirnov Denis

Reputation: 45

Use binding to Name property to expander visibility with own converter

        <Expander Visibility="{Binding Path=Name, Converter={StaticResource EmptyStringToVisibility}}">
             <Expander.Header>
                 <TextBlock Text="{Binding Path=Name}"/>
             </Expander.Header>
        </Expander>

Converter for example:

    class EmptyStringToVisibility : IValueConverter
    {
         public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
         {
             return String.IsNullOrEmpty(value as string) ? Visibility.Collapsed : Visibility.Visible;
         }

         public object ConvertBack(object value, Type targetType, object parameter,  System.Globalization.CultureInfo culture)
         {
             throw new NotImplementedException();
         }
    }

Upvotes: 0

Heena
Heena

Reputation: 8644

You can take reference from this example. Hide Expander ToggleButton if no child items in WPF

Xaml

  <ListBox x:Name="lstbx">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Expander x:Name="exp">
                <Expander.Header>
                    <TextBlock Text="{Binding Path=Name}"></TextBlock>
                </Expander.Header>
                <Expander.Style>
                    <Style TargetType="Expander">                          
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding Path=Name}" Value="{x:Null}">
                                <Setter  Property="Visibility" Value="Collapsed"/>
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </Expander.Style>
            </Expander>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

c#

     public Window1()
    {
        InitializeComponent();
        List<HeaderList> lst = new List<HeaderList>();
        lst.Add(new HeaderList(){Name= "Header1"});
        lst.Add(new HeaderList() { Name = "Header2" });
        lst.Add(new HeaderList() { });
        lst.Add(new HeaderList() { Name = "Header4" });
        lst.Add(new HeaderList() { });
        lst.Add(new HeaderList() { });
        lst.Add(new HeaderList() { Name = "Header7" });
        this.DataContext = this;
        lstbx.ItemsSource = lst;     
    }
}
public class HeaderList
{
    public string Name { get; set; }
}

Result

enter image description here

Upvotes: 3

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