I have an ItemsControl bound to a Dictionary and am trying to apply a template based on the value of the Dictionaries key. I am trying to do:
<ItemsControl ItemsSource="{Binding Path=CommonItems, Mode=OneWay}">
<ItemsControl.Style>
<Style TargetType="ItemsControl">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Key}" Value="authentication">
<Setter Property="ItemTemplate" Value="{StaticResource AuthenticationTemplate}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ItemsControl.Style>
</ItemsControl>
That doesn't work at all and my errors say Key doesn't exist on ItemsControl. That leads me to believe that It is using my TargetType to search for the binding. So how do I do this and have it actually use the ItemsSource?
If you want to do this per-item, i would suggest using an ItemTemplateSelector.
Related
I tried this for a while now and searched in the web without success... Now I dare to ask on stackoverflow myself.
So, the aim is to separate the definitions of the ItemContainerStyle and the ContentTemplate of a ListBoxItem. I have defined the ListBoxItemStyle in a ResourceDictionary and two different DataTemplates in the Window.Resources.
I now like to set the style of the ListBoxItem according to the one defined in the ResourceDictionary and change the DataTemplate with a trigger (IsMouseOver).
My (not working) Code so fare looks like this:
<ListBox HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Margin="20,60,10,10"
Grid.Row="1" Grid.Column="0"
PreviewMouseMove="DragMove_PreviewMouseMove"
PreviewMouseLeftButtonDown="Drag_PreviewMouseLeftButtonDown"
ItemsSource="{Binding Persons}" VerticalContentAlignment="Center"
Style="{StaticResource DefaultListBoxStyle}">
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="Style" Value="{StaticResource DefaultListBoxItemStyle}"/>
<Setter Property="ContentTemplate" Value="{StaticResource PersonsListBoxItemTemplate_default}"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="ContentTemplate" Value="{StaticResource PersonsListBoxItemTemplate_infoButtons}"/>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
where DefaultListBoxStyle is the style defined in the ResourceDictionary and PersonsListBoxItemTemplate_default & PersonsListBoxItemTemplate_infoButtons are the DataTemplates defined in the Window.Resources.
Now I get an error, that the style-object must not have an impact on the style-property of the object it belongs to.
I tried different ways, but without success... I also tried to define the style first and then change the template, but it does not work either.
Thank you all for your help!
So you can't set Style Property in Style with Setter. For this you need to use BasedOn:
<Style TargetType="ListBoxItem" BasedOn="{StaticResource DefaultListBoxItemStyle}">
<Setter ... />
</Style>
I have a ListView and inside this another ListView. Whenever I select an item in a child ListView I want the parent of that to be selected in the parent ListView. Example:
<Window>
<Window.Resources>
<!-- Parent ListView ItemsTemplate... Incomplete -->
<DataTemplate x:Key="parentItemTemplate">
<!-- Child ListView -->
<ListView SelectedItem="{Binding ChildSelectedItem}" ItemsSource="{Binding WhateverInParent}">
<ListView.Resources>
<Style TargetType="ListViewItem">
<Trigger Property="IsSelected" Value="True">
<!-- This is what I want to do, but ofc this doesn't work because it produces a compile error saying can't set TargetName in a setter -->
<Setter TargetName="parent" Property="SelectedValue" Value="{Binding DataContext, RelativeSource={RelativeSource AncestorType=ListView}}" />
</Trigger>
</Style>
</ListView.Resources>
</ListView>
</DataTemplate>
</Window.Resources>
<ListView ItemsTemplate="{StaticResource parentItemTemplate}" x:Name="parent" SelectedItem="{Binding ParentSelectedItem}" ItemsSource="{Binding Whatever}"/>
</Window>
How do I get this done? Would prefer it to be in XAML.
You just need to set the ListViewItem.ItemContainerStyle like below to achieve what you want
<ListView ItemsTemplate="{StaticResource parentItemTemplate}" x:Name="parent" SelectedItem="{Binding ParentSelectedItem}" ItemsSource="{Binding Whatever}">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Style.Triggers>
<Trigger Property="IsKeyboardFocusWithin" Value="true">
<Setter Property="IsSelected" Value="true" />
</Trigger>
</Style.Triggers>
</Style>
</ListView.ItemContainerStyle>
</ListView>
You could simply use the InnerControl class to achieve this.
References:
WPF Nested ListViews - selectedValue of parent ListView
Or else you can go for RelativeSource:
How to access controls parent's property in a style
Hope it helps!
I am trying to switch the content of a contentpresenter based on a datatrigger.I want to display a usercontrol in the contentpresenter.content, if i have a value set or else i need to display an error message.But the binding on my datatrigger fails stating that the property is not found.I cant get the datacontext to inherit for the datatrigger checking.I can make it work by using the commented out code.But i am confused why it doesn't work the normal way.
<ContentPresenter.Style>
<Style TargetType="{x:Type ContentPresenter}">
<Setter Property="Content" Value="{Binding UC}"/>
<Style.Triggers>
<!--<DataTrigger Binding="{Binding DataContext.HasValue,RelativeSource={RelativeSource AncestorType={x:Type ContentPresenter}}}" Value="false">
<Setter Property="Content" Value="No preview"/>
</DataTrigger>-->
<DataTrigger Binding="{Binding HasValue}" Value="false">
<Setter Property="Content" Value="No value"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ContentPresenter.Style>
</ContentPresenter>
If you want to use triggers to display UserControl, you should use ContentControl not ContentPresenter.
I prefer to use ContentPresenter for CustomControls and When I am using the UserControl for views of Custom Data Types in my system and Allow to give dynamic behavior.
Example: To switch templates for ContentPresenter you need to set ContentTemplateSelector like this
<ContentPresenter Content="{Binding MyContent}"
ContentTemplate="{Binding MyContentTemplate}"
ContentTemplateSelector="{Binding MyContentTemplateSelector}"/>
MyContent, MyContentTemplate & MyContentTemplateSelector are Dependency Properties and can be binded wherever you are using its instance.
READ :
Usage of ContentPresenter
What is the difference between ContentControl and ContentPresenter
The binding mentioned in the question won't work as
ContentPresenter’s DataContext is automatically set to the value of
its Content property, while ContentControl’s DataContext is not.
Bindings are resolved relatively to the value of the DataContext property. If you declare a binding on the ContentPresenter, the moment its content is set, the binding would be re-evaluated.
ContentControl.Content Property can be changed on any trigger based on your requirement. If you want to use it to change on PropertyChanged Event of a property of ViewModel, DataTrigger can be used by binding it with a DataTemplate with UserControl instance in it or using static resource of that UserControl.
<ContentControl>
<ContentControl.Style>
<Style TargetType="{x:Type ContentControl}">
<Setter Value="{StaticResource UnSelectedDataTemplate}" Property="ContentTemplate" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=IsSelected}" Value="True">
<Setter Value="{StaticResource SelectedDataTemplate}" Property="ContentTemplate" />
</DataTrigger>
</Style.Triggers>
</Style>
</ContentContro.Style>
</ContentControl>
READ How to use triggers for content template, more details here
Difference in DataTemplate and StaticResource scope is DataTemplate creates a new instance of the template every time its applied.
Whereas, StaticResource is using the same instance of UserControl again (Static Instance).
You can also use EventTriggers to change content base don Control Events like MouseOver etc.
Alternate approach
Very similar to the above with slight difference. Defining as a data template in resources. Triggering for the content change is essentially identical.
...in <x.Resources /> tag:
<DataTemplate x:Key="DesignerTemplate" DataType="{x:Type vm:SolutionViewModel}">
<vw:SolutionDesignerView />
</DataTemplate>
<DataTemplate DataType="{x:Type vm:SolutionViewModel}">
<ContentControl Content="{Binding }">
<ContentControl.Style>
<Style TargetType="{x:Type ContentControl}">
<Style.Triggers>
<DataTrigger Binding="{Binding IsLoaded}" Value="True">
<Setter Property="ContentTemplate" Value="{StaticResource DesignerTemplate}" />
</DataTrigger>
</Style.Triggers>
</Style>
</ContentControl.Style>
</ContentControl>
</DataTemplate>
...then:
<ContentControl Content="{Binding Solution}" />
I usually use trigger Like this...
<UserControl>
<UserControl.Resources>
<DataTemplate x:Key="normalTemplate" >
<!-Fav UserControl->
</DataTemplate >
<DataTemplate x:Key="overWriteTempalte">
<!-Fav UserControl-> </DataTemplate>
</UserControl.Resources>
<ContentPresenter x:Name="ContentField"
Content="{Binding}"
ContentTemplate="{StaticResource ResourceKey=normalTemplate}" />
<UserControl.Triggers>
<DataTrigger Binding="{Binding Path=MyProperty}" Value="True">
<Setter TargetName="ContentField" Property="ContentTemplate" Value="{StaticResource ResourceKey=overWriteTempalte}" />
</DataTrigger>
</UserControl.Triggers>
</UserControl>
If Bindings are a problem Use Snoop to Detect binding errors
I am trying to change the visibility with a trigger when a particular value in a combobox is selected, and I got the following XAML
<ItemsControl ItemsSource="{Binding AccessControl.Credentials}" >
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid >
<ComboBox Name="chkFieldType"
SelectedValue="{Binding Path=ValueSourceType,Converter={StaticResource enumstringConv}}"
SelectedValuePath="Tag" SelectionChanged="chkFieldType_SelectionChanged" >
<ComboBoxItem Tag="User">User</ComboBoxItem>
<ComboBoxItem Tag="SessionCredential">Field</ComboBoxItem>
<ComboBoxItem Tag="Inherit">From other Resource</ComboBoxItem>
</ComboBox>
<Border " Visibility="Hidden">
<Border.Resources>
<Style TargetType="{x:Type Border}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=SelectedValue, ElementName=chkFieldType}" Value="Inherit">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</Border.Resources>
<ComboBox/>
</Border>
In this case a border. The selected value is "Inherit" of type string but the border remainds hidden.
I ran into the same problem and found that you have to set the visibility property using the style only. So instead of having the initial visibility set with:
<Border Visibility="Hidden">
You should set the initial visibility using the style:
<Style TargetType="....">
<Setter Property="Visibility" Value="Hidden"/>
<Style.Triggers>
....
</Style.Triggers>
</Style>
(I know it's kinda overdue but I thought maybe someone else might run into the same problem).
Try SelectedItem.Tag or SelectedItem.Content instead of SelectedValue
Set your binding on SelectedValue, not SelectedItem.SelectedValue. The way you currently have it, it is looking for ComboBoxItem.SelectedValue, which doesn't exist
<DataTrigger Value="Inherit"
Binding="{Binding Path=SelectedValue,
Converter={StaticResource enumstringConv},
ElementName=chkFieldType}">
I think it's because you are putting the DataTrigger in Border.Resources.
Try putting the style in the window.resources, with a x:key in order to apply the style to the border.
I think that the border.resources can not access to a control "outside it's own resources context"
SelectedItem and SelectedValue are two seperate properties on the ComboBox.
Since your ComboBoxItems are all strings you can change
<DataTrigger Binding="{Binding Path=SelectedItem.SelectedValue, ElementName=chkFieldType}" Value="Inherit">
to
<DataTrigger Binding="{Binding Path=SelectedItem, ElementName=chkFieldType}" Value="Inherit">
I ended up setting the visibility manually via the code behind when the selectedItem event is fired..
I'm thinking out different ways to have a WPF ComboBox show blank as if nothing is selected when IsEnabled is set to false. Like always I'm trying to do this without having to redefine the whole control template for the ComboBox which is always a struggle I have with WPF. If anybody has any solutions more elegant than redefining the whole ComboBox control template please let me know.
The reason for what I'm trying to do is I have a CheckBox that represents an "All" option and when checked it disables the ComboBox which is used to pick only a single individual item. If my CheckBox is checked it is sometimes confusing to the users to see a value remaining in the ComboBox since that value has no meaning in that state of the UI.
Another requirement is that the solution cannot modify the SelectedValue, SelectedIndex, or SelectedItem values of the ComboBox since I would like to retain the previuosly selected item in the case that the users unchecks the "All" CheckBox.
Solution based on HCL's answer:
<ComboBox IsEnabled="{Binding ElementName=myCheckBox, Path=IsChecked}"
ItemsSource="{Binding Path=MyItems}"
SelectedValue="{Binding Path=MySelectedItem}">
<ComboBox.ItemTemplate>
<DataTemplate>
<ContentControl x:Name="content" Content="{Binding MyItemDescription}" />
<DataTemplate.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ComboBox}, Path=IsEnabled}"
Value="False">
<Setter TargetName="content"
Property="Visibility"
Value="Hidden" />
</DataTrigger>
</DataTemplate.Triggers>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
You can do something with triggers:
Try setting the ItemTemplate to an empty DataTemplate when the box is disabled. This will affect the rendering of the selected item and therefore hide it.
Another simple but not very nice solution would be to set the foreground color to the same as a background color.
I believe you can do this with a Style, rather than redefining the control template. Use a Trigger on the IsEnabled property to set the text shown in the ComboBox. Altering the SelectedItem would be my first approach, but since you don't want to do that, you may find success setting the DisplayMemberPath. Something like this (untested)...
<Style TargetType="{x:Type ComboBox}">
<Style.Triggers>
<Trigger Property="IsEnabled" Value="False">
<Trigger.Setters>
<Setter Property="DisplayMemberPath" Value="{x:Null}"/>
</Trigger.Setters>
</Trigger>
</Style.Triggers>
</Style>
Here's a style that does what you want. It employs a technique that I use all the time: a grid that contains multiple versions of the control, and data triggers that ensure that only one version is visible at any one time.
<ComboBox.Style>
<Style TargetType="ComboBox">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ComboBox">
<DockPanel>
<CheckBox x:Name="IsActive" DockPanel.Dock="Left"/>
<Grid>
<ComboBox
ItemsSource="{TemplateBinding ItemsSource}"
SelectedItem="{TemplateBinding SelectedItem}"
SelectedIndex="{TemplateBinding SelectedIndex}"
SelectedValue="{TemplateBinding SelectedValue}">
<ComboBox.Style>
<Style TargetType="ComboBox">
<Setter Property="Visibility" Value="Visible"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=IsActive, Path=IsChecked}" Value="False">
<Setter Property="Visibility" Value="Collapsed"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ComboBox.Style>
</ComboBox>
<ComboBox>
<ComboBox.Style>
<Style TargetType="ComboBox">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=IsActive, Path=IsChecked}" Value="False">
<Setter Property="Visibility" Value="Visible"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ComboBox.Style>
</ComboBox>
</Grid>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ComboBox.Style>
This preserves the selected item, selected index, and selected value, just as you want. In fact, it does this a little too well; there's not actually a way of telling that the user deactivated the combo box, since there's no property on ComboBox that exposes this information. I'd probably actually implement this as a custom control derived from ComboBox that exposed the value of the check box as an IsActive property. There are lots of other ways to do it.