Column Visibility fails sometimes when using GroupColumns in XamGrid

210

eno posted over 11 years ago

When using GroupColumns in XamGrid if the Visbility of Columns within a GroupColumn become Colapsed the GroupColumn will also become colasped. This is the behaviour expected however once the GroupColumn has become colapsed even when the Columns within that GroupColumn become Visible again the GroupColumn will never become Visible again.

Here is an example:

Xaml:

<Window.Resources>

</Window.Resources>

</StackPanel>

<ig:XamGrid AutoGenerateColumns="False" ItemsSource="{Binding DataSource}">

<ig:XamGrid.Columns>

<ig:GroupColumn Key="AB" >

<ig:GroupColumn.Columns>

<ig:TextColumn Key="A" Visibility="{Binding Source={x:Reference A}, Path=IsChecked, Converter={StaticResource BooleanToVisibilityConverter}}"/>

<ig:TextColumn Key="B" Visibility="{Binding Source={x:Reference B}, Path=IsChecked, Converter={StaticResource BooleanToVisibilityConverter}}"/>

</ig:GroupColumn.Columns>

</ig:GroupColumn>

</ig:XamGrid.Columns>

</ig:XamGrid>

</DockPanel>

Code behind:

public partial class MainWindow

{

public IEnumerable<Field> DataSource { get; set; }

public MainWindow()

{

InitializeComponent();

DataContext = this;

DataSource =

new[]

{

new Field {A = 1, B = 2},

new Field {A = 2, B = 3},

new Field {A = 3, B = 4}

};

}

public class Field

{

public int A { get; set; }

public int B { get; set; }

}

In the example above if you uncheck then recheck A leaving B checked the column Visibility changes as expected. However if you uncheck both A and B then recheck either or both, neither will show again.

I have also tried doing a MultiBinding on the GroupColumn to the Visibility of it's children Columns but that also did not help. Does anyone know of a solution to this?

Thanks

210

Verified Answer
eno posted over 11 years ago in reply to Maria Tsvyatkova

Thanks for following this up Maria. I can confirm that the solution you provided works.

To summarise for anyone else interested in how to work around this - you need to hook into ColumnVisibilityChanged event on XamGrid with the the following handler:

private void OnColumnVisibilityChanged(object sender, ColumnVisibilityChangedEventArgs e)
{
GroupColumn.Visibility = Visibility.Visible;
}
Cancel
Reply

Reject Answer

Cancel
17475

Offline Maria Tsvyatkova posted over 11 years ago in reply to Maria Tsvyatkova

Hi Eno,

I am just checking if my last reply was helpful for you. If you have any other questions on column visibility, please feel free to let me know.
Cancel
Reply

Verify Answer

Cancel
17475

Verified Answer
Offline Maria Tsvyatkova posted over 11 years ago in reply to eno

Hello Eno,

Thank you for the detail you had provided and I am sorry for the delay. I have created a sample project where the Visibility of the Group column is changed to Visible according to the number of its visible children columns. This could be achieved by calling the ColumnVisibilityChanged method of the grid when a checkbox is checked. When this event is called I check if the group column is collapsed and if it is, its Visibility property is set to Collapsed. I hope that this will help you in resolving the issue. Please feel free to ask if you have any questions.

XamGridGroupVis.zip
Cancel
Reply

Reject Answer

Cancel
210

eno posted over 11 years ago in reply to Maria Tsvyatkova

Hi Maria,

Here is a modification of the example above which shows the bindings being broken after the GroupColumn is automatically collapsed:

Xaml:

<Window.Resources>

<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>

<local:MultipleVisiblityConverter x:Key="MultipleVisiblityConverter"/>

</Window.Resources>

<DockPanel>

<StackPanel DockPanel.Dock="Top">

<CheckBox Name="ACheckBox" IsChecked="True">A</CheckBox>

<CheckBox Name="BCheckBox" IsChecked="True">B</CheckBox>

<TextBlock Text="{Binding ElementName=ATextColumn, Path=Visibility}"/>

<TextBlock Text="{Binding ElementName=BTextColumn, Path=Visibility}"/>

<TextBlock Text="{Binding ElementName=GroupColumn, Path=Visibility}"/>

</StackPanel>

<grids:XamGrid AutoGenerateColumns="False" ItemsSource="{Binding DataSource}">

<grids:XamGrid.Columns>

<grids:GroupColumn x:Name="GroupColumn" Key="AB" >

<grids:GroupColumn.Visibility>

<MultiBinding Converter="{StaticResource MultipleVisiblityConverter}">

<Binding ElementName="ATextColumn" Path="Visibility"/>

<Binding ElementName="BTextColumn" Path="Visibility"/>

</MultiBinding>

</grids:GroupColumn.Visibility>

<grids:GroupColumn.Columns>

<grids:TextColumn x:Name="ATextColumn" Key="A" Visibility="{Binding Source={x:Reference ACheckBox}, Path=IsChecked, Converter={StaticResource BooleanToVisibilityConverter}}"/>

<grids:TextColumn x:Name="BTextColumn" Key="B" Visibility="{Binding Source={x:Reference BCheckBox}, Path=IsChecked, Converter={StaticResource BooleanToVisibilityConverter}}"/>

</grids:GroupColumn.Columns>

</grids:GroupColumn>

</grids:XamGrid.Columns>

</grids:XamGrid>

</DockPanel>

Code behind:

public partial class MainWindow

{

public IEnumerable<Field> DataSource { get; set; }

public MainWindow()

{

InitializeComponent();

DataContext = this;

DataSource =

new[]

{

new Field {A = 1, B = 2},

new Field {A = 2, B = 3},

new Field {A = 3, B = 4}

};

}

}

public class Field

{

public int A { get; set; }

public int B { get; set; }

}

public class MultipleVisiblityConverter : IMultiValueConverter

{

public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)

{

if (values.Any(value => value == DependencyProperty.UnsetValue))

{

return DependencyProperty.UnsetValue;

}

return values

.OfType<Visibility>()

.Any(visibility => visibility == Visibility.Visible)

? Visibility.Visible

: Visibility.Collapsed;

}

public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)

{

throw new NotImplementedException();

}

}

In this example the GroupColumn Visibility is bound to the child TextColumns Visibility. The TextBlocks Text are bound to the Visibility of the columns. Notice how both the GroupColumn Visibility and the TextColumns Visilibity do not respond to the CheckBox bindings (as it looks like the bindings to the CheckBox is lost) after the GroupColumn becomes collapsed for the first time.

If you do have a way to make the Visibility bindings work please could you upload a sample?

Note: This is just a simple contrived example to isolate the issue for you to see. However in our actual use case the child columns Visibility property are bound using MultiBindings as they depend on a number of conditions. This makes writing custom code rather than making use of Bindings far more complicated.

Thanks
Cancel
Reply

Verify Answer

Cancel
17475

Offline Maria Tsvyatkova posted over 11 years ago in reply to eno

Hi,

The Visibility property of the last visible column is not changed to collapsed. Instead the GroupColumn is collapsed as it is explained in our documentation:

“If your end user tries to hide the last visible column of a GroupColumn, that particular column won’t hide, instead that GroupColumn will hide. For example, based on the above code snippet, if your end user has ProductID hidden, and then tries to hide ProductName, then the entire Product Information group will hide.”

In the attached sample the each TextColumn is bound to IsChecked property of a CheckBox but the visibility of the GroupColumn is not bound to any converter or property. When its value is changed automatically there is no functionality for setting it to visible again. If you bin dthe GroupColumn the same way the TextColumn “A” is bound, its visibility would be changed associated with the value of the IsChecked property of CheckBox “A”. This means that the binding functionality is working correctly.
Cancel
Reply

Verify Answer

Cancel