I have 2 DataTemplates (A & B). A contains an Expander and the expander's HeaderTemplate is pointed at another DataTemplate (B).
DataTemplate B is shown below:
<DataTemplate x:Key="ProjectExpanderHeader">
<Border CornerRadius="2,2,0,0"
Background="{StaticResource ItemGradient}"
HorizontalAlignment="{Binding HorizontalAlignment,
RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}},
Mode=OneWayToSource}">
<local:ItemContentsUserControl Height="30"/>
</Border>
</DataTemplate>
Is it possible to set the CornerRadius of B's Border when the IsExpanded property of A's Expander is set to true?
Thanks in advance.
You could do this by introducing a new attched property of type CornerRadius (e.g. Helper.CornerRadiusProperty) and attach it to a parent of your ExpanderHeader somewhere in DataTemplate A. You set this property based on IsExpanded using a trigger.
In your DataTemplate B you bind the CornerRadius of your Border to that property using FindAncestor:
<Border CornerRadius="{Binding local:Helper.CornerRadius,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type ContentPresenter}} ...
The above example assumes that you have set the Helper.CornerRadius property on a ContentPresenter in DataTemplate A.
I found my solution. I added the following code to DataTemplateB's Triggers. What it does is look for an ancestor expander control and applies the CornerRadius property to it.
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Expander}},Path=IsExpanded}" Value="false">
<Setter TargetName="ProjectExpanderHeader" Property="CornerRadius" Value="2,2,2,2"/>
</DataTrigger>
</DataTemplate.Triggers>
Why not using the triggers ?
<DataTemplate>
<Border CornerRadius="2,2,0,0"
Background="{StaticResource ItemGradient}"
HorizontalAlignment="{Binding HorizontalAlignment,
RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ContentPresenter}},
Mode=OneWayToSource}">
<Border.Style>
<Style>
<Style.Triggers>
<DataTrigger Binding="{Binding DataTemplateA.IsExpanded}"
Value="True">
<Setter Property="Border.CornerRadius"
Value="2,2,0,0" />
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
<local:ItemContentsUserControl Height="30" />
</Border>
</DataTemplate>
Related
Why is it that the binding Marked stops working when the triggers are used? Is there some way to fix this?
The multi selection ListBox has ListBoxItems with CheckBoxes, and the checkbox in an item is ticked when the corresponding item is selected, using mouse or keyboard or touch or whatever. The point with this demo is to not tick the checkboxes directly, but just multiselect the items and see the checkboxes get ticked as a consequence of that. This synchronization in the XAML works well, but since the Marked binding isn't working, the model won't get updated.
If I remove the triggers, then the binding Marked starts working. I know, because then the model gets updated when the checkboxes are ticked.
If I attach event handlers for Checked and Unchecked to the CheckBox, they fire even when the triggers are there.
<ListBox ItemsSource="{Binding Lines}" SelectionMode="Extended">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<CheckBox x:Name="cb"
Content="{Binding DisplayText}"
IsChecked="{Binding Marked, Mode=TwoWay}">
</CheckBox>
</StackPanel>
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type ListBoxItem}}, Path=IsSelected}" Value="true">
<Setter TargetName="cb" Property="IsChecked" Value="true"/>
</DataTrigger>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type ListBoxItem}}, Path=IsSelected}" Value="false">
<Setter TargetName="cb" Property="IsChecked" Value="false"/>
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
EDIT:
Although the accepted solution below is good XAML, it crashes with Elmish.WPF, which I'm using. That's another issue, and will be solved through other forums.
The DataTriggers will obviously override the Binding, since the ListBoxItem's IsSelected property is always either true or false.
Replace the DataTriggers by an ItemContainerStyle:
<ListBox ItemsSource="{Binding Lines}" SelectionMode="Extended">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox Content="{Binding DisplayText}"
IsChecked="{Binding Marked}"/>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="IsSelected" Value="{Binding Marked}"/>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
I have Visibility bound to a bool, which works perfectly. However when editing the page the Border is not visible. I have to delete the Visibility Binding, make my changes and redo the Visibility Binding.
I'm pretty sure I saw there is a way to set a "editing default", but I cannot find that link anymore (or remember what it was called). Can someone explain how to set the default to visible so I can see it whilst editing, but not affect it's operation at runtime?
<Border Grid.Column="2" BorderBrush="HotPink" BorderThickness="2" MinHeight="100" MinWidth="100"
Visibility="{Binding ElementName=GenerateWorkOrders, Path=IsChecked, Converter={StaticResource booleanToVisibility}, UpdateSourceTrigger=PropertyChanged}">
<Label Content="Not Visible While Editing"/>
</Border>
The problem is that the default value of IsChecked of GenerateWorkOrders CheckBox is false
If IsChecked have Binding, you can use FallbackValue:
<CheckBox x:Name="GenerateWorkOrders" IsChecked="{Binding SomeProperty, FallbackValue=True}" />
Another way is to avoid the binding, you can use the DesignerProperties.IsInDesignMode Attached Properties that indicate if you in design mode (More inforamtion).
You can use this property in behavior, or in XAML only approach:
<Border Grid.Column="2" BorderBrush="HotPink" BorderThickness="2" MinHeight="100" MinWidth="100">
<Border.Style>
<Style TargetType="{x:Type Border}">
<Setter Property="Visibility" Value="{Binding ElementName=GenerateWorkOrders, Path=IsChecked, Converter={StaticResource booleanToVisibilityConverter}, UpdateSourceTrigger=PropertyChanged}" />
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=(componentModel:DesignerProperties.IsInDesignMode)}" Value="true">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Style>
<Label Content="Not Visible While Editing"/>
</Border>
Referencing to this question: WPF Databinding: How do I access the "parent" data context?
I wanna do something similiar, but for the header of a Groupbox (because the header does not concern with the Box is being disabled and thus is always black while the rest is light gray. This looks a bit strange to me if all the content of the box is gray, the above is gray, but the box title itself stays black.
So I tried to use the approach mentioned in the linked question by flq to simply bind the isEnabled property of the header textblock to the isEnabled property of the groupbox but it seems that my binding at some point fails and I don't know where and why exactly.
heres my current code:
<GroupBox Header="Change Steps" Grid.Row="2" Grid.ColumnSpan="3" Name="gbChangeSteps">
<GroupBox.Style>
<Style TargetType="GroupBox">
<Setter Property="HeaderTemplate">
<Setter.Value>
<DataTemplate>
<TextBlock Text="{Binding}" FontWeight="Bold" Height="19" Foreground="Black" IsEnabled="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type GroupBox}}, Path=isEnabled}"/>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupBox.Style>
<!-- ... (some non relevant Content)-->
</GroupBox>
after additional research I found the post Disable groupBox including the groupBox name in WPF
that lead me, in combination with Properties->Create Databinding->Binding type->UIElement to the solution that fixed both problems, the one this question was about and the original one that lead to entire restyling, which was that letters like the small g got messed up in the header.
This is the code that fixed the issue:
<GroupBox.Style>
<Style TargetType="{x:Type GroupBox}">
<Setter Property="HeaderTemplate">
<Setter.Value>
<DataTemplate>
<TextBlock Text="{Binding}" FontWeight="Bold" Height="19" IsEnabled="{Binding IsEnabled, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UIElement}}}">
<TextBlock.Style>
<Style>
<Style.Triggers>
<Trigger Property="Control.IsEnabled" Value="False">
<Setter Property="Control.Foreground" Value ="#FF6D6D6D" />
</Trigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupBox.Style>
I have several StackPanels that change visibility based on ToggleButtons. The code below works if I replace Tag with btn1 on the DataTrigger-lines.
How do I use the value of the Tag property?
<Window x:Class="MyTestApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="TestApp">
<Window.Resources>
<Style x:Key="panelStyle" TargetType="{x:Type StackPanel}">
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=Tag, Path=IsChecked}" Value="False">
<Setter Property="StackPanel.Visibility" Value="Collapsed" />
</DataTrigger>
<DataTrigger Binding="{Binding ElementName=Tag, Path=IsChecked}" Value="True">
<Setter Property="StackPanel.Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<WrapPanel>
<ToggleButton Content="One" Name="btn1" />
<ToggleButton Content="Two" Name="btn2" />
<StackPanel Style="{StaticResource panelStyle}" Tag="{Binding btn1}">
<Label Content="Data to panel 1" />
</StackPanel>
<StackPanel Style="{StaticResource panelStyle}" Tag="{Binding btn2}">
<Label Content="Data to panel 2" />
</StackPanel>
</WrapPanel>
</Window>
This question is very similar, but I'm missing details on how to pass an element name.
XAML - Generic textbox stylewith triggers / parameters?
Your bindings are incorrect.
In your DataTemplate the bindings should be:
<DataTrigger Binding="{Binding Path=Tag.IsChecked, RelativeSource={RelativeSource Self}}" Value="False">
<Setter Property="StackPanel.Visibility" Value="Collapsed" />
</DataTrigger>
Here the RelativeSource with a mode of Self tells the binding engine that the object to bind against is object to which the style is being applied (e.g. your StackPanel). The PropertyPath of Tag.IsChecked tells the binding engine to look for a property called IsChecked from the object stored in Tag.
Finally the bindings in your StackPanel should be:
<StackPanel Style="{StaticResource panelStyle}" Tag="{Binding ElementName=btn1}">
<Label Content="Data to panel 1" />
</StackPanel>
Here ElementName creates a binding to another element in the logical tree. If you do not explicitly assign to any properties in a Binding as in your original example:
Tag="{Binding btn1}"
The value specified is assigned to the Path property. So this would be the same as:
Tag="{Binding Path=btn1}"
Also note, that using Tag is not considered best practice since it's type is of object and its use is unrestricted, and hence can take on any number of different meanings throughout your project (which often makes it difficult to understand, especially when used in Templates that are located far away from their actual use).
Hope this helps!
Use Converter: set the visibility of StackPanel:
<StackPanel Visivility="{Binding IsChecked, ElementName=btn1, Converter={StaticResource BooleanToVisibilityConverter}}">
...
</StackPanel>
I have a problem. I made a DataTemplate for a TreeView and I need to set the initial value of the ToggleButton's IsChecked property depending on my model. But it turns out that setting this property using triggers/setters disables the databinding.
Is it so? If yes, give me a suggestion how it can be fixed?
<DataTemplate x:Key="CellTemplate_Name">
<DockPanel x:Name="dock">
<ToggleButton x:Name="Expander"
IsChecked="{Binding Path=IsExpanded, RelativeSource={RelativeSource AncestorType={x:Type TreeViewItem}}}"> <--- Binding
...
<ToggleButton/>
...
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding Path=ObjIsOpened, Converter={StaticResource DebugConverter}}" Value="true"> <--- Trigger
<Setter TargetName="Expander" Property="IsChecked" Value="true"></Setter>
</DataTrigger>
...
</DataTemplate.Triggers>
</DataTemplate>
Regards, Lerax.
First of all I suggest you read the excellent article by Josh Smith
Simplifying the WPF TreeView by Using the ViewModel Pattern
Based on that article, I would suggest defining a style for the TreeViewItem (using the ItemContainerStyle property of the TreeView) which binds its IsExpanded property to your model object's ObjIsOpened property. Then get rid of your trigger.
Example:
<Style TargetType="TreeViewItem">
<Setter Property="IsExpanded"
Value="{Binding ObjIsOpened, Converter={StaticResource DebugConverter}}"/>
</Style>
<DataTemplate x:Key="CellTemplate_Name">
<DockPanel x:Name="dock">
<ToggleButton x:Name="Expander"
IsChecked="{Binding Path=IsExpanded,
RelativeSource={RelativeSource
AncestorType={x:Type TreeViewItem}}}"> <--- Binding
...
<ToggleButton/>
...
</DataTemplate>
I suspect they do not disable data binding, they just have higher priority. Instead of using binding and trigger at the same time, why don't you use one of them (either binding or trigger)? E.g. you could bind to model directly, and don't use trigger at all...