Naming Control Contained Within Custom WPF GroupBox - wpf

I've got a custom GroupBox control that essentially does nothing more than apply a style
<GroupBox x:Class="SharedResources.Controls.StyledGroupBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<GroupBox.Style>
<Style TargetType="{x:Type GroupBox}">
<Setter Property="BorderBrush" Value="#D5DFE5"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupBox}">
...
<ContentPresenter Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="2"
Margin="{TemplateBinding Padding}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupBox.Style>
</GroupBox>
The problem is that when I come to use this, if I set x:Name property of the content of the StyledGroupBox, then I get the following error:
Cannot set Name attribute value 'name' on element ''. '' is under the scope of element 'StyledGroupBox', which already had a name registered when it was defined in another scope
Any ideas how I can resolve this?

Don't use a UserControl just to define a Style (I'd love to know where this practice comes from because I've seen an explosion of it recently). Instead, create the Style as a resource in its own right and apply it to GroupBoxes as desired:
<Style TargetType="{x:Type GroupBox}">
<Setter Property="BorderBrush" Value="#D5DFE5"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupBox}">...
<ContentPresenter Grid.ColumnSpan="2" Grid.Column="1" Grid.Row="2" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
...
<GroupBox>
Will inherit the above style.
</GroupBox>

If anyone is trying to make this work (for something more/other than styles), see: How to create a WPF UserControl with NAMED content

Related

Xaml switch between TextBlock and TextBox

I've noticed that TextBoxes are very slow and create performance issues when the Text is changed dynamically by code (I need to change the Text continuosly to 10-15 TextBoxes at the same time), so, as a workaround, I've created a custom control with a TextBlock and a TextBox:
The TextBlock is used in almost all time.
The TextBox is used only when I need to edit the Text inside the control with keyboard.
My solution is to change the template and use the TextBox when the control is focused:
(Value is a string Dependency Property)
<Style TargetType="{x:Type local:CustomControl1}">
<Setter Property="Value" Value="Val"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl1}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Text="{TemplateBinding Value}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsFocused" Value="True">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:CustomControl1}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<TextBox HorizontalContentAlignment="Center" VerticalContentAlignment="Center"
Text="{Binding Path=Value, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
But when I click on the control nothing happens.
I think that the problem is that the "focus state" is passed to the internal TextBox, and the control loses the "focus state".
There is a better way to create a custom "TextBox" control like this, or a way to resolve this problem?
You don't need a custom control for this, that's just adding unnecessary overhead. What you're trying to create is still a TextBox, with all the usual behavior of a TextBox (focus etc). All you need to do is change the template to a TextBlock when it's not in focus:
<Window.Resources>
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<Trigger Property="IsFocused" Value="False">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TextBox}">
<TextBlock Text="{TemplateBinding Text}" />
</ControlTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<TextBox Text="Hello World" />
<TextBox Text="Goodbye World" />
</StackPanel>

Binding a TextBlock back to ListBoxItem ItemSource

I have a ListBoxItem Style that I am trying to modify so that it will show character ellipsis when the list box is made to small. To do that I've had to get rid of the ContentPresenter in our code and replace it with a TextBlock. The ListBoxes that this is applied to are all bound via the ItemSource property.
Here is my code.
<Style x:Key="ListBoxItemStyle" TargetType="{x:Type ListBoxItem}">
<Setter Property="Background" Value="White"/>
<Setter Property="Margin" Value="0,0,0,0"/>
<Setter Property="Padding" Value="0,0,0,0"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<Grid>
<Border x:Name="Bd" SnapsToDevicePixels="true">
<!-- Before this used to be ContentPresenter but I switched it to TextBlock to get it the TextTrimming property. I can't find the right way to bind the data though.-->
<TextBlock Text="{TemplateBinding DisplayMemberPath}" TextTrimming="CharacterEllipsis" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
</Border>
<Rectangle x:Name="HoverRectangle"
Stroke="{StaticResource Gold}"
StrokeDashCap="Square"
StrokeThickness="0"
SnapsToDevicePixels="True" />
<Rectangle x:Name="KeyboardFocusRectangle"
Height="Auto"
SnapsToDevicePixels="True"
Stroke="{StaticResource BrightBlue}"
StrokeDashCap="Square"
StrokeThickness="0" />
</Grid>
<ControlTemplate.Triggers>
<!-- Bunch of Triggers in here -->
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
My current TextBlock Text binding (Text="{TemplateBinding DisplayMemberPath}") is not working. What should the binding be in order to work correctly?
Your only reasonable choice here is to assume the data context of the ListBoxItem is a string, or can be displayed as such:
<TextBlock Text="{Binding}" .../>

xaml border style

I create style for buttons:
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="#8A88E1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse Fill="{TemplateBinding Background}"/>
<ContentPresenter HorizontalAlignment="Center"
VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
It all OK. Now I want to write part of the style that would be looked around the ellipse boundary.
Erno beat me to the answer, but here's an example:
<Style TargetType="{x:Type Button}">
<Setter Property="Background" Value="#8A88E1"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid>
<Ellipse Fill="{TemplateBinding Background}" Stroke="..." StrokeThickness="..." />
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
You should be able to bind the Stroke to the parent BorderBrush but I haven't tested it: Stroke="{TemplateBinding BorderBrush}". However, you won't be able to directly bind StrokeThickness to the parent BorderThickness as they're two different types (Ellipse.StrokeThickness is uniform and a simple double value whereas Button.BorderThickness is of type Thickness.).
There are two options:
Set the Stroke and StrokeThickness of the ellipse or
Add a template to the border and use an ellipse in the template.
Let me know if you need help with these.

Why define a Template inside a Style in xaml, WPF?

I've been wondering this ever since I started using MS's control templates examples as basis to build custom controls.
take the Label example for instance: http://msdn.microsoft.com/en-us/library/ms752327.aspx
why on earth is it defined like this:
<Style x:Key="{x:Type Label}" TargetType="Label">
<Setter Property="HorizontalContentAlignment" Value="Left" />
<Setter Property="VerticalContentAlignment" Value="Top" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Label">
<Border>
<ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
RecognizesAccessKey="True" />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground">
<Setter.Value>
<SolidColorBrush Color="{DynamicResource DisabledForegroundColor}" />
</Setter.Value>
</Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
and not like this directly:
<ControlTemplate x:Key="{x:Type Label}" TargetType="Label">
<Border>
<ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
RecognizesAccessKey="True" />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground">
<Setter.Value>
<SolidColorBrush Color="{DynamicResource DisabledForegroundColor}" />
</Setter.Value>
</Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
and then called as a template directly and not through the style property?
is there a hidden reason I do not see for doing things like this? or is it just one way of doing things and that's it?
(NB: don't tell me this is because of the horizontal and vertical alignment setters! we all know those are the default values for a label and this is basically useless if you keep those values)
Without using a Style it's not possible to automatically assign the template to all instances of a specific control type. Setting x:Key="{x:Type Label}" for the control template does not automatically apply this template to all controls of type Label.
You can make a style apply to all buttons below the declaration in the visual tree by setting the TargetType to Button, but you can't do the same with a template, if you do not wrap it inside a Style that have a Setter for the template.
Also, note that in your example you can exchange
<Style x:Key="{x:Type Label}" TargetType="Label">
With
<Style TargetType="Label">
As the x:Key is set to the TargetType if the x:Key definition is omitted.

WPF Template Inheritance

I created a button. My basic requirements are rounded thicker border, with more than one color (i.e. for Buy/Sell buttons)
I was hoping that i could create the template once, and than just override the border brush like this:
<Style x:Key="BorderButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border BorderThickness="2"
BorderBrush="Red"
CornerRadius="3"
Background="{x:Null}">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="GreenBorderButton" BasedOn="{StaticResource BorderButton}" TargetType="{x:Type Button}">
<Setter Property="BorderBrush" Value="Green" />
</Style>
but they both produce the same style.
Do i need to write out the whole template every time? seems like unnecessary code repetition (especially if 3-4 colors are desired). Hoping there is some way to inherit a template.
Your code is very close to working; the issue is that GreenBorderButton is applying the BorderBrush to the button itself, not the Border in the overridden Template.
To fix this, simply change the Border's BorderBrush to use the parent Button's BorderBrush. You can do this using a TemplateBinding like so:
<Style x:Key="BorderButton">
<Setter Property="Control.Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Border x:Name="border"
BorderThickness="2"
BorderBrush="{TemplateBinding Property=BorderBrush}"
CornerRadius="3"
Background="{x:Null}">
<ContentPresenter HorizontalAlignment="Center" VerticalAlignment="Center"/>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Then, you can either use the same overridden styles like you have, or you could simply do:
<Button Style="{StaticResource BorderButton}" BorderBrush="Blue" Content="Blue" />

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