In a UserControl XAML file, I want to define a ListView based on the predefined style. So I write the following lines:
<ListView Grid.Column="2" SelectionMode="Single">
<ListView.ItemContainerStyle>
<Style
TargetType="{x:Type ListViewItem}"
BasedOn="{StaticResource {x:Type ListViewItem}}">
Though, for the BasedOn attribute, I get the error: The resource "{x:Type ListViewItem}" could not be resolved..
If I replace the ListViewItem word with ListBoxItem or TreeViewItem the compilation is successful, but at runtime it raises a System.InvalidOperationException exception, specifying that the BasedOn attribute needs a ListBoxItem.
If I remove that attribute, it works, but it has a weird look.
If you are using MahApps.Metro, you should base your Style on the MetroListViewItem resource:
<Style TargetType="{x:Type ListViewItem}"
BasedOn="{StaticResource MetroListViewItem}">
...
BasedOn is used for Style inheritance, so it should be pointing to another ListViewItem Style that you've previously defined, not a type.
<Style TargetType="{x:Type ListViewItem}"
BasedOn="{StaticResource MyListViewItemBaseStyle}">
Related
I know how to extend a style in XAML, i.e. for a TextBlock:
BasedOn="{StaticResource {x:Type TextBlock}}"
But if the control has a prefix, it throws an exception:
BasedOn="{StaticResource {x:Type Foo:MyControl}}"
What is the right syntax?
I found the reason for the error in the Style itself.
I know I'm a pervert, but I am very curious, is there a way to make custom controls to seek for it's base class style first, and then it's own.
Why I'm asking: I have some TreeView derived controls with custom item templates. I apply those templates, then I have a base style. Later I might apply some color palette. At the last step I have a problem. I need to apply 2 styles. PVStructuralTree is derived from TreeView it has some DependencyProperty DataTemplates that get inserted into resources in code.
PVStructuralTreeView
EmploeeTemplate
... more templates
Default style for PVStructuralTreeView:
<Style x:Key="DefaultPVStructuralTreeView" TargetType="{x:Type c:PVStructuralTreeView}" BasedOn="{StaticResource DefaultTreeView}">
<Setter Property="EmploeeTemplate"><!-- This get inserted inro Resources in code -->
<Setter.Value>
<DataTemplate DataType="{x:Type s:Emploee}">
...
</DataTemplate>
</Setter.Value>
</Setter>
... Lots of them here
</Style>
<Style TargetType="{x:Type c:PVStructuralTreeView}" BasedOn="{StaticResource DefaultPVStructuralTreeView}"/>
Default style for a TreeView (it's pretty big, so I won't post it here):
<Style TargetType="{x:Type TreeView}" BasedOn="{StaticResource DefaultTreeView}"/>
In color template.xaml file I'd like to have this + some magic to apply both styles at the same time (from Generic.xaml and themed one):
<Style x:Key="ThemedTreeView" TargetType="{x:Type TreeView}" BasedOn="{StaticResource DefaultTreeView}">
...
</Style>
<Style TargetType="{x:Type c:PVStructuralTreeView}" BasedOn="{StaticResource ThemedTreeView}"/>
But it just overwrites generic.xaml styles. I want it to add to it.
Now I'm doing this way:
<Style x:Key="ThemedPVStructuralTreeView" TargetType="{x:Type c:PVStructuralTreeView}" BasedOn="{StaticResource DefaultPVStructuralTreeView}">
... CopyPaste from ThemedTreeView ...
</Style>
<Style TargetType="{x:Type c:PVStructuralTreeView}" BasedOn="{StaticResource ThemedPVStructuralTreeView}"/>
Does anyone knows the way how to reuse the ThemedTreeView style here?
You can base a Style on Another (one only!) Style using the BasedOn property and override specific properties, but you cannot base a DataTemplate or a ControlTemplate on another template. This is not supported. A template must be defined as a whole:
WPF: Is there a way to override part of a ControlTemplate without redefining the whole style?
I have some locally defined styles within Window.Resources. I have some styles for a TextBlock, TextBox, CheckBox and RadioButton. These are supposed to be applied to all controls in the window, so I haven't provided a value for x:Key. I would like them to inherit from a style targeting FrameworkElement. So I have something like:
<Style TargetType="{x:Type RadioButton}">
...
</Style>
<Style TargetType="{x:Type TextBlock}">
...
</Style>
<Style TargetType="{x:Type TextBox}">
...
</Style>
<Style TargetType="{x:Type CheckBox}">
...
</Style>
<Style x:Key="TriggerBase" TargetType="{x:Type FrameworkElement}">
<Style.Triggers>
<Trigger Property="UIElement.IsMouseOver" Value="True">
...
</Trigger>
</Style.Triggers>
</Style>
My problem is that I am unable to set the BasedOn property to inherit from my TriggerBase style. After looking at similar questions, such as this and this, I still cannot get it working. These answers suggest you need to specify the TargetType on your base style, which I have done.
I thought maybe the Styles have to target the exact same type, but after digging around on MSDN I found that wasn't the problem:
If you create a style with a TargetType property and base it on another style that also defines a TargetType property, the target type of the derived style must be the same as or be derived from the type of the base style.
If I set BasedOn like BasedOn="{DynamicResource TriggerBase}", it can find my TriggerBase, but I get an error stating:
A 'DynamicResourceExtension' cannot be set on the 'BasedOn' property
of type 'Style'. A 'DynamicResourceExtension' can only be set on a
DependencyProperty of a DependencyObject.
If I try BasedOn="{StaticResource TriggerBase}", I get an error that it cannot find TriggerBase. One of the linked answers above showed using StaticResource like BasedOn="{StaticResource {x:Type FrameworkElement}, but it still cannot resolve the style.
How can I inherit from the TriggerBase style? I'm targeting .NET 4.5.
You are correct and you can base your styles on FrameworkElement style just need to move
<Style x:Key="TriggerBase" TargetType="{x:Type FrameworkElement}">
</Style>
to the top and then
<Style TargetType="{x:Type RadioButton}" BasedOn="{StaticResource TriggerBase}">
will work
I am trying to make a custom style for a TabItem Header. I got it to work by accident.
this fails:
<Style TargetType="{x:Type TabItem}" x:Name="TabHeader3" x:Key="test">
but this works
<Style TargetType="{x:Type TabItem}" x:Name="TabHeader3">
What's going on?
The first Style you have defined is an "explicit" Style, so you must explicitly use it like so:
<TabItem Style="{StaticResource test}" />
The second Style you have defined is an "implicit" Style. So it will be applied to all TabItem controls below it in the visual/logical tree, or to all TabItem controls if it's defined in the application resources.
Your second Style is equivalent to:
<Style TargetType="{x:Type TabItem}" x:Name="TabHeader3" x:Key="{x:Type TabItem}">
So the key is the Type of the object to which it should be applied.
If a TabItem has a Style explicitly defined (like I show above), then any implicit Styles will not be used. Also, if you have two implicit Styles defined, then the closest one wins. So here:
<Window>
<Window.Resources>
<Style TargetType="{x:Type TabItem}">
<Setter Property="Background" Value="Red" />
</Style>
</Window.Resources>
<Grid>
<Grid.Resources>
<Style TargetType="{x:Type TabItem}">
<Setter Property="Background" Value="Blue" />
</Style>
</Grid.Resources>
...
<TabItem ... />
...
</Grid>
</Window>
The Blue Style will take precedence over the Red Style.
Finally, you generally don't need to include x:Name on your Styles.
If you add the style to a resource dictionary without a key then the style gets applied to all TabItems that are within the scope of the resource dictionary by default. If you add a Key to the style then you need to manually set the Style
Is there a way I can reuse Styles for more than 1 TargetType eg. ComboBox and TextBox
<Style TargetType="ComboBox, TextBox" />
is there such a thing? Or is the only way duplicate the style and target each style to differnt types?
You can't (if I'm not mistaken).
But what you may do in order to avoid copy-paste is to create a BaseStyle with a key and then create two styles for ComboBox and TextBox which are BasedOn the BaseStyle. smth like that:
<Style x:Key="BaseStyle" TargetType="{x:Type Control}">
<Setter ... />
</Style>
<Style BasedOn="{StaticResource BaseStyle }" TargetType="{x:Type ComboBox }" />
<Style BasedOn="{StaticResource BaseStyle }" TargetType="{x:Type TextBox}" />
Instead of this you can provide targettype as control and define setter proeprties of control and apply that style to textbox and combox.