I'd like to have page headers in my app with either an icon or text centered in a 50px high bar at the top of the page. Optionally with a back-button.
For this reason I use a UserControl on each page which gets either one of those styles applied: PageHeaderStyle or PageHeaderBackStyle.
My implementation of one of those is the following (style definition in my App.xaml):
<Style x:Key="PageHeaderBaseStyle" TargetType="UserControl">
<Setter Property="HorizontalAlignment" Value="Stretch" />
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="Height" Value="50" />
<Setter Property="Width" Value="NaN" />
<Setter Property="Background" Value="{StaticResource CDColor}" />
</Style>
<Style x:Key="PageHeaderStyle" TargetType="UserControl" BasedOn="{StaticResource PageHeaderBaseStyle}">
<Setter Property="Content">
<Setter.Value>
<Grid Background="{StaticResource CDColor}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" DataContext="{StaticResource MainPageModel}">
<TextBlock Style="{StaticResource PageHeaderTextBlockStyle}" Text="{Binding Title}" Visibility="{Binding TitleVisibility}" />
<Image Style="{StaticResource PageHeaderIconStyle}" Source="{Binding Icon}" Visibility="{Binding IconVisibility}" />
</Grid>
</Setter.Value>
</Setter>
</Style>
Applied like it should be:
<UserControl Style="{StaticResource PageHeaderStyle}" />
Now first I had used "Template" and applied a DataTemplate with the grid component. But this didn't work. Then I changed it to directly set the Content of the UserControl. This does work: After building the designer shows the page header (before it showed only the blue selection border, but no content - it was transparent).
But as soon as I start debugging the app on the emulator it disappears and the running app only shows a blank spot where it should be.
Why is this so? I mean after all the designer already shows it, why does it disappear then, though?
FYI: I do not get any binding exceptions nor any other. It just doesn't show up.
PS: I tried setting the Background in the base style while setting the grid's background to transparent. This didn't work either - only a blank spot.
Solved the problem: Best approach is probably to use a ContentControl. Using the Content property did not work, though. You have to use the ContentTemplate property. Using that one does work just fine.
Related
I'm trying out styles in avalonia and most works, except for pseudoclasses, they just get ignored.
I have created a window and all styles are in there and I have created a user control (with a button on - the pseudoclasses are on the button), using the styles. I do not use code, only xaml to define the styles.
I have tried it out in the "Style Selector" for the button as "Button:pseudoclassname" and "Button.le:pseudoclassname". I have also tried "Button:pointerover" and "Button:hover" as the documentation mentions that that could be modified. No result. The styles for the pseudoclasses are all ignored, the others are all executed correct.
Is there something I'm doing wrong or is this a bug in avalonia ?
The xaml windows file:
<Window xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:views="clr-namespace:Hub.Views"
xmlns:vm="using:Hub.ViewModels"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
x:Class="Hub.Views.MainWindow"
Icon="/Assets/avalonia-logo.ico"
Width="200" Height="300"
Title="Hub"
Classes="le">
<Window.Styles>
<Style Selector="Window.le">
<Setter Property="Background" Value="#191919"/>
</Style>
<Style Selector="Button.le">
<Setter Property="Background" Value="green"/>
<Setter Property="Foreground" Value="white"/>
</Style>
<Style Selector="Button.le:pointerover">
<Setter Property="Background" Value="red"/>
<Setter Property="Foreground" Value="white"/>
</Style>
<Style Selector="Button.le:pressed">
<Setter Property="Background" Value="blue"/>
<Setter Property="Foreground" Value="white"/>
</Style>
<Style Selector="TextBlock.le_update">
<Setter Property="FontStyle" Value="Italic"/>
<Setter Property="FontSize" Value="17"/>
<Setter Property="FontFamily" Value="Arial, Verdana"/>
<Setter Property="Foreground" Value="white"/>
<Setter Property="Background" Value="transparent"/>
</Style>
</Window.Styles>
<views:UpdateView/>
</Window>
The xaml user control file:
<UserControl xmlns="https://github.com/avaloniaui"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
x:Class="Hub.Views.UpdateView">
<DockPanel>
<StackPanel DockPanel.Dock="Bottom">
<Button Classes="le" HorizontalAlignment="Center" HorizontalContentAlignment="Center" Width="300">
Check for updates
</Button>
</StackPanel>
<StackPanel Spacing="5" Margin="5">
<TextBlock Classes="le_update" HorizontalAlignment="Center" Margin="4">
No updates for Hub.
</TextBlock>
<TextBlock Classes="le_update" HorizontalAlignment="Center" Margin="4">
No updates for Engine.
</TextBlock>
</StackPanel>
</DockPanel>
</UserControl>
Button's Background property does get affected by your style, but at that point it has no effect on the actual Button's background, because Background property controls only the normal state of the button.
If you take a look at the default Button style here you can see that it passes its background to ContentPresenter via TemplateBinding:
<Setter Property="Template">
<ControlTemplate>
<ContentPresenter x:Name="PART_ContentPresenter"
Background="{TemplateBinding Background}"
but overrides ContentPresenter's background in a style like this:
<Style Selector="Button:pointerover /template/ ContentPresenter#PART_ContentPresenter">
<Setter Property="Background" Value="{DynamicResource ButtonBackgroundPointerOver}" />
Since it's ContentPresenter that actually draws the background (Button is a lookless control), you'll see the button to have ButtonBackgroundPointerOver and not the Button's Background property value.
So, you need to write a style that changes the inner ContentPresenter like this:
<Style Selector="Button.le:pointerover /template/ ContentPresenter#PART_ContentPresenter">
<Setter Property="Background" Value="green" />
</Style>
Unfortunately that makes your styles theme-dependent since control templates are different between default and fluent themes.
The answer Kekekeks gave is the correct one for the question I asked.
However, I use this space in the hope to help novice users of avalonia with no background in xaml at all, like I do. Most of us look at avalonia to give our apps an interface that works on Windows/Mac/Linux. To be honest, at the moment of writing, no real alternatives in c# exist.
At this moment Avalonia does have examples and some documentation that is good, but not so for people not really having a background in xaml.
Therefore, go to Udemy or LikedIn.Learning or Youtube or wherever you find a good course on WPF AND AFTER THAT go to the documentation of Avalonia and start playing around.
The similarities that both (Avalonia and WPF) share is enormous !!! And yes it is mentioned a few times in the docs, but a blunt "Do go and learn WPF first if you are new to xaml !" on the frontpage of the documentation would have saved me a fair share of time in trying to find it all out via the website.
Fair is fair, the project still is in beta and the website is already well documented for that stage, so no blame to the team !
I have a quick (and most likely) easy question for which I unfortunately do not find a suitable solution. My requirements are as follows:
For the purpose of creating a navigation bar, I want to stack some buttons. For this purpose, I am using a stack panel.
Between each of the buttons, I want to have some space. I could of course set the margin for every button, however I find this solution not very robust and instead want to define the margin centrally.
What I therefore did is I defined a style within the stack panel and set the margin once. This works great with one issue: For the button I would love to use a style provided by Materialdesigninxaml. When I however set the style to the button, the margin style gets ignored.
Has anyone an idea or do I need to make use of a workaround?
Thank you guys for your help.
Here is my sample code which works as no Materialdesigninxaml style is defined:
<StackPanel.Resources>
<Style TargetType="{x:Type Button}">
<Setter Property="Margin" Value="0 10 0 0"/>
<Setter Property="Height" Value="50"/>
<Setter Property="Width" Value="150"/>
</Style>
</StackPanel.Resources>
<Button>
<StackPanel Orientation="Horizontal">
<materialDesign:PackIcon Kind="Database" VerticalAlignment="Center"/>
<TextBlock Text="BUTTON 1"/>
</StackPanel>
</Button>
This is my code with a specified Materialdesigninxaml style which does not work:
<StackPanel.Resources>
<Style TargetType="{x:Type Button}">
<Setter Property="Margin" Value="0 10 0 0"/>
<Setter Property="Height" Value="50"/>
<Setter Property="Width" Value="150"/>
</Style>
</StackPanel.Resources>
<Button Style="{DynamicResource MaterialDesignFlatButton}">
<StackPanel Orientation="Horizontal">
<materialDesign:PackIcon Kind="Database" VerticalAlignment="Center"/>
<TextBlock Text="BUTTON 1"/>
</StackPanel>
</Button>
I'm unable to left-align the contents of a Flyout.
Windows seems to automatically right-align flyout contents that display on the right side of the window. I tried setting the HorizontalAlignment property of the children, setting the Flyout.FlyoutPresenterStyle property HorizontalContentAlignment, and other HorizontalContentAlignment properties without success.
<StackPanel Orientation="Horizontal"
FlowDirection="RightToLeft">
<!-- Settings menu -->
<Button.Flyout>
<Flyout>
<Flyout.FlyoutPresenterStyle>
<Style TargetType="FlyoutPresenter">
<Setter Property="ScrollViewer.HorizontalScrollMode" Value="Disabled"/>
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled"/>
<Setter Property="HorizontalContentAlignment" Value="Left"/><!-- No -->
</Style>
</Flyout.FlyoutPresenterStyle>
<StackPanel HorizontalAlignment="Left"><!-- No -->
<TextBlock HorizontalAlignment="Left" HorizontalTextAlignment="Left">Settings</TextBlock><!-- No -->
…
</Button.Flyout>
</StackPanel>
I expect the flyout contents to align left, but they stay on the right.
Creating a reproducible example made me realize my error. The property FlowDirection was accidentally set as RightToLeft in a parent StackPanel. Reverting this solves the problem.
I would like to be able to create a custom pivot page title style in my application, so that I may use it across multiple pages. Essentially I just want the title of the Pivot to be centered with a certain font size and type. Originally I was using an Image for my title but I really need a text title instead. How might I go about doing this? I've already tried setting this within App.xaml and using it within my MainPage.xaml but so far I don't have anything working.
App.xaml (original)
<Style x:Key="ApplicationName" TargetType="Image">
<Setter Property="Height" Value="50"/>
<Setter Property="Width" Value="92.85"/>
<Setter Property="Margin" Value="-3,0,0,0"/>
<Setter Property="Source" Value="/Assets/ApplicationTitle.png"/>
</Style>
MainPage.xaml
<phone:Pivot x:Name="mainPagePivotControl" Style="{StaticResource PivotStyle}">
<phone:Pivot.TitleTemplate>
<DataTemplate>
<Image Style="{StaticResource ApplicationName}"/>
</DataTemplate>
</phone:Pivot.TitleTemplate>
...
</phone:Pivot>
I am writing a Store app with XAML and C#. I want to use Border and ViewBox. I got border styled, so I do not have to set properties that many times. I set BorderThickness to 2, and color to White, but this causes problems in my Viewbox.
Here it is in XAML:
<Viewbox Grid.Row="1" Stretch="Uniform">
<Grid Width="600" Height="600">
<Grid.Resources>
<Style TargetType="Border">
<Setter Property="BorderBrush" Value="White" />
<Setter Property="BorderThickness" Value="2" />
</Style>
<Style TargetType="Grid">
<Setter Property="VerticalAlignment" Value="Top" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="Width" Value="150" />
<Setter Property="Height" Value="150" />
</Style>
</Grid.Resources>
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<Grid>
<Border>
<Viewbox>
<TextBlock Text="T" />
</Viewbox>
</Border>
</Grid>
The result of this is:
The problem is the scaled border around the letter "T".
I do not want to remove above styling for Border in Grid.Resources. I found only one solution so far...
<Viewbox>
<Viewbox.Resources>
<Style TargetType="Border">
<Setter Property="BorderBrush" Value="White" />
<Setter Property="BorderThickness" Value="0" />
</Style>
</Viewbox.Resources>
<TextBlock Text="T" />
... what would give correct result:
, but I do not want to put these lines after each ViewBoxes, because there will be many.
I also tried to make a component, what has this default "resource" of zero thick border, but that had bad scaling.
So my question is how to to remove that border?
You're right to use the zero value for BorderThickness. There just might be another element in the visual tree hierarchy that also holds a default value that causes this.
I can't test this right now, but I can recommend this tool to you:
http://blois.us/Snoop/
You can inspect the visual tree with this by dragging the crosshair above your running debug application. Every time I stumbled upon a problem like this I found it highly useful to see which controls really appear at runtime, because with xaml it can be really tough to know it all. Hope you can find it!