I have used the following approach to bind IsSelected of my items to a Property: WPF ListView Programmatically Select Item
<ListView.ItemContainerStyle>
<Setter Property="IsSelected" Value="{Binding IsSelected}"/>
</ListView.ItemContainerStyle>
Now I am able to select my items in code behind by simple setting the IsSelected property to true. However I am not able to deselect items by setting the IsSelected property of my items to false.
Setting the items property IsSelected to true will trigger the ListViewSelectionChanged event. However setting the property IsSelected of an already selected item to false does not trigger the event. The property will be changed to false but the item remains selected within the ListView. I have also tried using Mode=TwoWay without any success.
I would appreciate any sort of help!
Thank you very much in advance,
Thomas
For OP or others looking to "programmatically" deselect a ListView.
If your ListView rigged up as Single, Extended or Multiple you can always just:
YourlistView.Selecteditem = null;
Or you can use this as well:
YourlistView.UnselectAll();
Looks like you are just missing the TargetType for the style. Add the target type of ListViewItem as per Kent's original code below.
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="IsSelected" Value="{Binding IsGroovy}"/>
</Style>
</ListView.ItemContainerStyle>
Related
I am trying to make the items of my WPF comboBox visible (preferably greyed out) but not allow the user to select them using c# code.
I have tried the following:
comboBoxName.IsHitTestVisible = false
comboBoxName.Focusable = false
However, this prevents them seeing the contents of the comboBox all together. How would I make the contents visible but cannot be selected in c#?
Set an item container style that will disable each ComboBoxItem.
<ComboBox x:Name="comboBoxName" ItemsSource="{Binding Collection}">
<ComboBox.ItemContainerStyle>
<Style TargetType="{x:Type ComboBoxItem}">
<Setter Property="IsEnabled" Value="False"/>
</Style>
</ComboBox.ItemContainerStyle>
</ComboBox>
If you use code-behind, can define and apply the item container style like this.
var itemContainerStyle = new Style(typeof(ComboBoxItem));
var isEnabledSetter = new Setter(IsEnabledProperty, false);
itemContainerStyle.Setters.Add(isEnabledSetter);
comboBoxName.ItemContainerStyle = itemContainerStyle;
I have this XAML in my RadDataGrid that changes the background color of a selected row to red based on the value returned by the ValidateModuleBank property defined in my model.
<tg:RadDataGrid.Resources>
<Style TargetType="gridPrimitives:SelectionRegionBackgroundControl">
<Setter Property="Background" Value="{Binding ValidateModuleBank,Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Style>
</tg:RadDataGrid.Resources>
I looked online and it says that UWP does not support binding to a property in a style. So, how can I achieve this?
Thanks in advance for your help.
I've got a WPF MultiSelectTreeView (downloaded from here: http://unclassified.software/en/source/multiselecttreeview).
Now I want to control, which items the user selects. A simple example is that he shouldn't be able to select child nodes of different parents. But there are also more ViewModel-specific use cases.
It's easy to achieve this in code-behind of the Window by using the PreviewSelectionChanged event, checking the conditions directly and setting the Cancel-flag accordingly. But since I want to obtain the separation of View and ViewModel, I am looking for a way of doing this in my WindowViewModel.
Of course you could also extract the check to the ViewModel and call it from the view, but it looks wrong:
WindowViewModel _viewModel;
void PreviewSelectionChanged(object sender, PreviewSelectionChangedEventArgs e)
{
e.Cancel = !this._viewModel.CanSelect(e.Item as TreeItemViewModel);
}
I hope that anybody has an idea.
- timnot90
Typically, when data binding a hierarchical collection to a TreeView in WPF, the custom data items should have an IsSelected property defined in their class. If they do, then it can be data bound to the IsSelected property of each TreeViewItem:
<TreeView ItemsSource="{Binding YourCollection}" ... >
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="IsSelected" Value="{Binding IsSelected}" />
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
When this is done, you can just set that property to true to select an item and to false to deselect an item.
// Select Item
dataObject.IsSelected = true;
// Deselect Item
dataObject.IsSelected = false;
You can add a handler to the PropertyChanged event of each item to detect when the IsSelected property changes (if they implement the INotifyPropertyChanged interface as expected).
I have a ContextMenu and a ColumnHeaderStyle defined in Window.Resource section which I use-it to a DataGrid ColumnHeader. My code is something like this:
<ContextMenu x:Key="cm_columnHeaderMenu"/>
<Style x:Key="DefaultColumnHeaderStyle" TargetType="{x:Type DataGridColumnHeader}">
<Setter Property="ContextMenu" Value="{StaticResource cm_columnHeaderMenu}" />
</Style>
<DataGrid Grid.Column="2" Grid.Row="1" x:Name="dgridFiles" IsReadOnly="True"
ColumnHeaderStyle="{StaticResource DefaultColumnHeaderStyle}">
I want to know if I can (and if the answer it true, then HOW I can I do it) bind the ContextMenu Visibility property to same control ContextMenu Items.Count > 0 property.
Initially based on some other treeView control selections made there shoud be no items in the context menu, but i wish to add dinamically items in ContextMenu based on selection in treeView. This part is done, the context has those items. On some selections there are no-items, but still on the grid it appears an empty ContextMenu. So I believe the easiest part it would be to bind the Visibility to Items.Count property of the same control.
Sorry if my english is not good enough, I'll try to explain better if i didnt make clear 1st time.
you want to bind via RelativeSource, especially the Self mode.
I think by reading this or this you will be able to achieve your goal.
Then you'll need a binding converter to convert the integer values to the matching type and values of the Visibility property. You'll find a short tutorial here.
Regards
Using this you can bind to the property in the same control
Visibility="{Binding Path=Items.Count, RelativeSource={RelativeSource Self}}"
You also have to use a converter to achieve what you want.
Just in case you need this
Try a converter to convert the value of the item count to a boolean. So you'll end up with something like
<ContextMenu Visibility={Binding RelativeSource={RelativeSource Self},
Converter={StaticResource ItemsToVisibilityConverter}, Path=Items.Count}} />
If that doesn't work, try this with data triggers (you still need a converter anyway, and this shows a converter at work):
http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/a8ad8c14-95aa-4ed4-b806-d0ae874a8d26/
I have a ListBox that when in focus, and when I have an item selected returns a valid SelectedIndex. If I have a valid SelectedIndex and I click on a TextBox on the same Forum, the SelectedIndex now becomes -1. However I want it to keep its SelectedIndex from changing. How would I go about doing this?
ListBox will keep it's SelectedIndex regardless of focus.
I tested it on a blank project with one ListBox, one TextBox and one Label used to display the ListBox's SelectedIndex. Under both the ListBox's SelectedIndexChanged and the TextBox's TextChanged events I updated the Label with the ListBox's SelectedIndex
There must be something else going on to cause the Selected Index to change to -1.
I had the same issue as original poster.
I couldn't figure it out totally but it seems like when you have the listbox bound to an observable collection and the collection gets changed that the selected item loses the focus.
I hacked around the issue by saving the selected index in a variable and resetting it if the selected index was -1 (and it was valid to restore it)
This is an old question, but in case someone else experiences the same problem check your ListBoxItem style especially if you are using one of styles from WPF Themes.
The problem with WPF Themes specifically is the inclusion of the
section outside of the Control Template:
<Style d:IsControlPart="True" TargetType="{x:Type ListBoxItem}">
....
<Style.Triggers>
<Trigger Property="Selector.IsSelected" Value="True">
<Setter Property="Foreground">
<Setter.Value>
<SolidColorBrush po:Freeze="True" Color="{DynamicResource BlackColor}" />
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="true">
<Setter Property="IsSelected" Value="true" />
</Trigger>
</Style.Triggers>
</Style>
Delete the Style.Triggers and the problem should go away
Handle the SelectedIndexChanged event and save the selected value so that you can restore it when your control regains focus.
I haven't verified this in my apps but if the SelectedIndex property changes when the LB loses focus you probably have to handle that case yourself by caching the last selected index and resetting it when the control regains focus. You can do this in the containing form or you can do it in a class derived from ListBox.
You could even try setting the selected index as soon as you see it becomes -1. Not sure what would happen but I'd be curious to find out....
Edit: just tested it and like the other poster I can't reproduce it either. Must be something slightly different about your LB
Are these controls in different dialogs, or maybe different tabs on a tabbed container? That's the only way I can think of that you would lose your SelectedIndex when changing focus. Otherwise, how would anybody e.g. click a button to take action on an item? You'd lose the selection when focus went to the button you're clicking...