How can i get the base view's control

[lishuangquan1987]

Environment

Avalonia 11.1.3
Windows

Questing

Below is my avalonia Project:

BaseAView.axaml

<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"
             xmlns:view="clr-namespace:Ava_Demo.Views"
             xmlns:vm="clr-namespace:Ava_Demo.ViewModels"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="Ava_Demo.Views.BaseAView" 
             x:Name="UserControl"
             x:DataType="vm:MainWindowViewModel">
    <Grid RowDefinitions="40,*">
        <StackPanel Orientation="Horizontal" Background="LightBlue">
            <TextBlock Text="this is BaseA view"></TextBlock>
            <Button Content="Test" Name="BtnTest" Width="100" Height="30" x:FieldModifier="public"></Button>
        </StackPanel>
        <ContentControl Grid.Row="1" Content="{Binding #UserControl.MainContent}"></ContentControl>
    </Grid>
</UserControl>

BaseAView.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Markup.Xaml;

namespace Ava_Demo.Views;

public partial class BaseAView : UserControl
{
    public BaseAView()
    {
        InitializeComponent();
    }
    
    public static readonly StyledProperty<object?> MainContentProperty = AvaloniaProperty.Register<BaseAView, object?>(
        nameof(MainContent));

    public object? MainContent
    {
        get => GetValue(MainContentProperty);
        set => SetValue(MainContentProperty, value);
    }
}

AView.axaml

<view:BaseAView 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"
             xmlns:view="clr-namespace:Ava_Demo.Views"
             xmlns:vm="clr-namespace:Ava_Demo.ViewModels"
             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
             x:Class="Ava_Demo.Views.AView"
             x:DataType="vm:MainWindowViewModel">
    <view:BaseAView.MainContent>
        <TextBlock>this is A view</TextBlock>
    </view:BaseAView.MainContent>
</view:BaseAView>

AView.axaml.cs

using Avalonia;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Markup.Xaml;

namespace Ava_Demo.Views;

public partial class AView : BaseAView
{
    public AView()
    {
        InitializeComponent();
    }

    protected override void OnLoaded(RoutedEventArgs e)
    {
        base.OnLoaded(e);

        var btn = this.FindControl<Button>("BtnTest");//return null
    }
}

MainWindow.axaml

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="using:Ava_Demo.ViewModels"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:view="clr-namespace:Ava_Demo.Views"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Ava_Demo.Views.MainWindow"
        x:DataType="vm:MainWindowViewModel"
        Icon="/Assets/avalonia-logo.ico"
        Title="Ava_Demo">

    <Design.DataContext>
        <!-- This only sets the DataContext for the previewer in an IDE,
             to set the actual DataContext for runtime, set the DataContext property in code (look at App.axaml.cs) -->
        <vm:MainWindowViewModel/>
    </Design.DataContext>

    <view:AView></view:AView>

</Window>

my question is:I can not get the BtnTest from BaseAView.Below is my debug with break point,any one can help me? thanks

[stevemonaco]

That XAML isn't available. When AView is constructed, BaseAView has its ctor ran first (which calls InitializeComponent and loads BaseAView.axaml), then the AView ctor runs (which calls InitializeComponent which loads AView.axaml). This replaces the XAML content, so nothing from BaseAView.axaml is available.

I suggest finding a different pattern. Don't try to inherit classes and expect to inherit XAML. Composition is your friend here.

[lishuangquan1987]

OK，thanks for your response，I just want to share some axaml code from base view and do not want to write the same code.