Auto hide empty category

Hi Benjamin,

In that sample, we added an IsVisible property to the CustomPropertyModel class that inherits our PropertyDescriptorPropertyModel class.  You would probably need to do the same kind of thing by making a CustomCategoryModel and have it inherit our CategoryModel.  You could override the factory.CreateCategoryModel method to create your instance instead.  In the MainControl.xaml, you'd have to set the CategoryStyle property to a similar Style as the one for PropertyStyle. 

Perhaps when your CustomPropertyModel's IsVisible value changes, you could look at its Parent and if it's a CustomCategoryModel, call its InvalidateIsVisible method too.  Then the CustomCategoryModel.IsVisible property would need to look at its contained properties and see if any were visible for it to be true.

That is probably the general approach we'd take to get categories hiding as well.

Hello,

Thank you very much, this solution is perfect.

Benjamin.

Hello,

This worked fine until I introduced nested categories. The solution isn’t complicated, but it took me a while to figure out, so I’m sharing it here in case it helps anyone.

As I mentioned, when the IsVisible value of my CustomPropertyModel changes, it calls InvalidateIsVisible if its Parent is a CustomCategoryModel. For a nested category, it’s just as simple: if its Parent is also a CustomCategoryModel, it calls InvalidateIsVisible as well!

Benjamin

Hi BenjaminLopVic,

Can you please share  a code sample for the same.

Hello,

If its not too late, here is a sample for an auto-hidding category that becomes hidden when all its children are hidden:

interface IHideableElement
{
    bool IsVisible { get; }
}

class CustomPropertyModel : PropertyDescriptorPropertyModel, IHideableElement
{
    private bool? isVisible;

    private void InvalidateIsVisible()
    {
        isVisible = null;
        this.NotifyPropertyChanged(nameof(IsVisible));
        if (this.Parent is AutoHiddingCategoryModel customCategoryModel)
        {
            customCategoryModel.InvalidateIsVisible();
        }
    }

    public bool IsVisible
    {
        get
        {
            if (!isVisible.HasValue)
            {
                //Get whether the propertyModel should be visible or not
            }

            return isVisible.Value;
        }
    }
}

class AutoHiddingCategoryModel : CategoryModel, IHideableElement
{
    private bool? isVisible;

    internal void InvalidateIsVisible()
    {
        isVisible = null;
        this.NotifyPropertyChanged(nameof(IsVisible));
        if (this.Parent is AutoHiddingCategoryModel customCategoryModel)
        {
            customCategoryModel.InvalidateIsVisible();
        }
    }

    public bool IsVisible
    {
        get
        {
            if (!isVisible.HasValue)
            {
                isVisible = Children.Any(model => model is IHideableElement iVisibility && iVisibility.IsVisible);
            }

            return isVisible.Value;
        }
    }
}

And you can invalidate the visibility of a property when the value changes, for example :

protected override void OnPropertyChanged(PropertyChangedEventArgs e)
{
    base.OnPropertyChanged(e);

    if (e.PropertyName == nameof(ValueAsString))
    {
        InvalidateIsVisible();
    }
}

Thanks for the code snippet. Just one question.
In the MainControl.xaml, Are you setting style for both CategoryStyle and PropertyStyle. Can you share the code for the xaml too.

Yes, I forget that :

 <Style x:Key="CategoryPropertyGridItemStyle" TargetType="grids:PropertyGridItem" >
     <Setter Property="Background" Value="{DynamicResource {x:Static themes:AssetResourceKeys.ListGridLineBackgroundNormalBrushKey}}" />
     <Setter Property="BorderThickness" Value="0" />
     <Setter Property="FontWeight" Value="Bold" />
     <Setter Property="Padding" Value="5,3" />

     <Setter Property="Template">
         <Setter.Value>
             <ControlTemplate TargetType="grids:PropertyGridItem">
                 <Border x:Name="gridLineBorder" BorderBrush="{TemplateBinding GridLineBrush}" BorderThickness="0,0,0,1" SnapsToDevicePixels="True">
                     <Border Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}">
                         <gridsPrimitives:PropertyGridItemContentPanel>
                             <gridsPrimitives:TreeItemExpansionToggleButton x:Name="PART_ExpanderButton" Style="{TemplateBinding ToggleExpansionButtonStyle}" 
								Visibility="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsExpandable, Converter={StaticResource BooleanToVisibilityConverter}}" 
								IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsExpanded, Mode=TwoWay}" />

                             <shared:PixelSnapper VerticalRoundMode="CeilingToEven">
                                 <Grid HorizontalAlignment="Left">
                                     <Rectangle x:Name="focusVisual" Margin="0,1" StrokeThickness="1" 
											   Stroke="{DynamicResource {x:Static themes:AssetResourceKeys.ContainerForegroundLowDisabledBrushKey}}" StrokeDashArray="1 2" 
											   SnapsToDevicePixels="True" Visibility="Collapsed" />

                                     <TextBlock Margin="{TemplateBinding Padding}" Text="{Binding DisplayName}" TextTrimming="CharacterEllipsis" VerticalAlignment="Center" />
                                 </Grid>
                             </shared:PixelSnapper>
                         </gridsPrimitives:PropertyGridItemContentPanel>
                     </Border>
                 </Border>

                 <ControlTemplate.Triggers>
                     <Trigger Property="GridLineBrush" Value="{x:Null}">
                         <Setter TargetName="gridLineBorder" Property="BorderThickness" Value="0" />
                     </Trigger>
                     <MultiTrigger>
                         <MultiTrigger.Conditions>
                             <Condition Property="IsSelected" Value="true" />
                             <Condition Property="grids:TreeListBox.IsSelectionActive" Value="true" />
                         </MultiTrigger.Conditions>
                         <Setter TargetName="focusVisual" Property="Visibility" Value="Visible" />
                     </MultiTrigger>
                 </ControlTemplate.Triggers>
             </ControlTemplate>
         </Setter.Value>
     </Setter>
 </Style>

And in my PropertyGrid :

<grids:PropertyGrid.ItemContainerStyleSelector>
    <grids:PropertyGridItemStyleSelector>
        <grids:PropertyGridItemStyleSelector.PropertyStyle>
            <Style TargetType="grids:PropertyGridItem">
                <Setter Property="Visibility" Value="{Binding IsVisible, Converter={StaticResource BooleanToVisibilityConverter}}" />
            </Style>
        </grids:PropertyGridItemStyleSelector.PropertyStyle>
        <grids:PropertyGridItemStyleSelector.CategoryStyle>
            <Style TargetType="grids:PropertyGridItem" BasedOn="{StaticResource CategoryPropertyGridItemStyle}">
                <Setter Property="Visibility" Value="{Binding IsVisible, Converter={StaticResource BooleanToVisibilityConverter}}" />
            </Style>
        </grids:PropertyGridItemStyleSelector.CategoryStyle>
    </grids:PropertyGridItemStyleSelector>
</grids:PropertyGrid.ItemContainerStyleSelector>

Thanks for the quick response. It was quite helpful.