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XAML DataTrigger Not Firing?

I have a property in my ModularClientModule class called ExistsOnDisk. When that property is set to false, I want to disable the CheckBox. For some reason, this does not seem to work despite me putting it last in the Triggers XAML block, which means it should be the last thing to fire. I.e, nothing should be interfering. I know my code-behind should be correct because as you will see below, I have another control which receives the update and fires fine.
This one here responds to the ExistsOnDisk property change without issue, and strikesthrough the text:
GridViewColumn x:Name="FileNameHeader" Header="File Name">
<GridViewColumn.CellTemplate>
<DataTemplate DataType="{x:Type local:ModularClientModuleUI}">
<TextBlock Text="{Binding Filename}">
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Style.Triggers>
<DataTrigger Binding="{Binding ExistsOnDisk}" Value="False">
<Setter Property="TextDecorations" Value="Strikethrough"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
This one here does not, and the checkbox remains enabled:
<GridViewColumn x:Name="StatusHeader" Header="Status">
<GridViewColumn.CellTemplate>
<DataTemplate DataType="{x:Type local:ModularClientModuleUI}">
<StackPanel>
<CheckBox x:Name="ClientModuleStatusCheckBox" Margin="5, 0" Click="ClientModuleStatusCheckBox_Click" IsEnabled ="{Binding Client.Online}">
<CheckBox.Style>
<Style TargetType="{x:Type CheckBox}" BasedOn="{StaticResource MahApps.Styles.CheckBox}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding LoadState}" Value="Loaded">
<Setter Property="IsChecked" Value="True" />
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding LoadState}" Value="Unloaded">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
<DataTrigger Binding="{Binding LoadState}" Value="Loading">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
<DataTrigger Binding="{Binding ExistsOnDisk}" Value="True">
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding ExistsOnDisk}" Value="False">
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>
What could be going on here?

Set the default value of the IsEnabled using a Setter and remove IsEnabled ="{Binding Client.Online}" from the <CheckBox> element:
<CheckBox x:Name="ClientModuleStatusCheckBox" Margin="5, 0" Click="ClientModuleStatusCheckBox_Click">
<CheckBox.Style>
<Style TargetType="{x:Type CheckBox}" BasedOn="{StaticResource MahApps.Styles.CheckBox}">
<Setter Property="IsEnabled" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding LoadState}" Value="Loaded">
<Setter Property="IsChecked" Value="True" />
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding LoadState}" Value="Unloaded">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
<DataTrigger Binding="{Binding LoadState}" Value="Loading">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
<DataTrigger Binding="{Binding ExistsOnDisk}" Value="True">
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>
Also note that you shouldn't use more than one trigger on the same bool property.

WPF treeview item visibility binding to property + static variable

I have a WPF treeview, with nodes visibility dependent on their "Deleted" binding property:
<Style x:Name="SelectedTreeItem" TargetType="TreeViewItem">
<EventSetter Event="MouseRightButtonDown" Handler="TreeSetup_MouseRightButtonDown"/>
<Setter Property="IsSelected" Value="{Binding Path=IsSelected, Mode=TwoWay}" />
<Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
<Setter Property="Visibility" Value="Visible" />
<Style.Triggers>
<DataTrigger Binding="{Binding Deleted}" Value="True">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
</Style.Triggers>
</Style>
I would like to make add some way to ignore this deleted property value. This would be achieved by a button "Show deleted items".
I do not want to change the "Deleted" value, but rather add a global condition to that forces this binding to ignore untill the button is pressed again.

You can do that via MultiDataTrigger.Conditions. Here is an example for visibility:
<Style>
<Setter Property="Control.Visibility" Value="Visible" />
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Path=IsPropA}" Value="false" />
<Condition Binding="{Binding Path=IsPropB}" Value="false" />
</MultiDataTrigger.Conditions>
<Setter Property="Control.Visibility" Value="Hidden" />
</MultiDataTrigger>
</Style.Triggers>
</Style>

I used the other answer in conjuction with a static resource
<Style>
<Setter Property="Control.Visibility" Value="Visible" />
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Path=IsPropA}" Value="false" />
<Condition Binding="{Binding Source={StaticResource ClassName},Path=PropertyName}" Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="Control.Visibility" Value="Hidden" />
</MultiDataTrigger>
</Style.Triggers>
</Style>
Just had to create the local resource under Window resources:
<Window.Resources>
<local:ClassName x:Key="ClassName"/>
And then the button used to show deleted or not:
private void btnApply_Click(object sender, RoutedEventArgs e)
{
//ApplyGeneralChanges();
var item = this.FindResource("ClassName") as ClassName;
item.DisplayDeleted = !item.DisplayDeleted;
}

Text.IsEmpty Opposite

i have this CheckBox
<CheckBox VerticalAlignment="Center" Name="CheckItem"
IsChecked="{Binding ElementName=Faccette, Path=Text.isEmpty, Mode=OneWay}"
/>
Faccette is a TextBlock, i need the opposite of the Text.isEmpty.
Is it possible without a Converter?

You may use a Style with DataTriggers:
<CheckBox>
<CheckBox.Style>
<Style TargetType="CheckBox">
<Setter Property="IsChecked" Value="True"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=Faccette, Path=Text}" Value="">
<Setter Property="IsChecked" Value="False"/>
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=Faccette, Path=Text}" Value="{x:Null}">
<Setter Property="IsChecked" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>

Changing checkbox of column type DataGridCheckBoxColumn using DataTrigger

I currently have another issue opened related to the DataGrid but I thought I'd open another
I'm trying to change the status of a checkbox automatically based on the value of another column, but how do I do this using the DataGridCheckBoxColumn? I was using the 'IsSelected' but eventually realized this property applied to the cell rather than the checkbox.
Here's my code
<DataGridCheckBoxColumn Header="Active" Binding="{Binding IsActive}">
<DataGridCheckBoxColumn.CellStyle>
<Style TargetType="DataGridCell">
<Style.Triggers>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="" >
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="01" >
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="02" >
<Setter Property="IsSelected" Value="True" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="03" >
<Setter Property="IsSelected" Value="False" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</DataGridCheckBoxColumn.CellStyle>
</DataGridCheckBoxColumn>
As you can see, I want to select the checkbox automatically when the LocationText is 2 and unselect it when the LocationText is 3.
Any ideas?
Update 1:
I thought I figured it out when I tried the following:
<DataGridCheckBoxColumn.ElementStyle>
<Style TargetType="CheckBox">
<Setter Property="HorizontalAlignment" Value="Center" />
<Setter Property="VerticalAlignment" Value="Center" />
<Style.Triggers>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="01" >
<Setter Property="IsChecked" Value="False" />
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="02" >
<Setter Property="IsChecked" Value="True" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
<DataTrigger Binding="{Binding SelectedLocation.LocationText}" Value="03" >
<Setter Property="IsChecked" Value="False" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</DataGridCheckBoxColumn.ElementStyle>
But to no avail. It disables the checkbox alright but it refuses to check it.
Frustrating...

it should be
<DataGrid.Columns>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate >
<DataTemplate x:Name="dtAllChkBx">
<CheckBox Name="cbxAll">
<CheckBox.Style>
<Style TargetType="CheckBox">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=wndMain, Path=LocationText , Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Value="" >
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=wndMain, Path=LocationText, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Value="01" >
<Setter Property="IsEnabled" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=wndMain, Path=LocationText, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Value="02" >
<Setter Property="IsChecked" Value="True" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=wndMain, Path=LocationText, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Value="03" >
<Setter Property="IsChecked" Value="False" />
<Setter Property="IsEnabled" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
and datacontext must be implement INotifyPropertyChanged
and when binded property changed it needs to notify property changed.

How to set TabIndex in Hyperlink?

I am new to WPF, I dont know how to do this.
I tried following code -
<TextBlock Grid.Column="3" Grid.Row="3" Visibility="{Binding Path=CanCreate, Converter={StaticResource BoolVisibilityConverter}}">
<Hyperlink KeyboardNavigation.TabIndex="2" Command="{Binding Path=CreateCommand}">Create
<Hyperlink.Style>
<Style TargetType="{x:Type Hyperlink}">
<Setter Property="KeyboardNavigation.IsTabStop" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=CanCreate, Converter={StaticResource BoolVisibilityConverter}}">
<Setter Property="KeyboardNavigation.IsTabStop" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
</Hyperlink.Style>
</Hyperlink>
</TextBlock>
Visibility depends on CanCreate Dependency property. Here IsTabStop is not enabling. Can anyone suggest the solution. Thanks in advance.
Requirement
I want to set TabIndex to hyperlink when it is visible.

You don't need a converter in the DataTrigger change your Hyperlink.Style to:
<Hyperlink.Style>
<Style TargetType="{x:Type Hyperlink}">
<Setter Property="KeyboardNavigation.IsTabStop" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=CanCreate}" Value="True">
<Setter Property="KeyboardNavigation.IsTabStop" Value="True" />
</DataTrigger>
</Style.Triggers>
</Style>
</Hyperlink.Style>
EDIT: You may also want to remove focus when your TextBlock and Hyperlink is invisible, you can do it by adding another DataTrigger:
<Hyperlink.Style>
<Style TargetType="{x:Type Hyperlink}">
<Setter Property="KeyboardNavigation.IsTabStop" Value="False" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=CanCreate}" Value="True">
<Setter Property="KeyboardNavigation.IsTabStop" Value="True" />
</DataTrigger>
<DataTrigger Binding="{Binding Path=CanCreate}" Value="False">
<Setter Property="Focusable" Value="False" />
</DataTrigger>
</Style.Triggers>
</Style>
</Hyperlink.Style>