Control 'SettingsView' is a top level control and cannot be added as a child.

[SirZeeno]

I am trying to instantiate a SettingsView on a button press and want to show it as soon as it gets instantiated, but I am getting this error telling me that SettingsViw is a top level and cannot be added as a child. I don't even know where I am adding it as a child and I am confused as to what happened since it worked before some changes I have made to it.

This is the ViewModel

public class SettingsViewModel : ViewModelBase
{
    private SearchEngine _searchEngine;
    
    public SearchEngine SearchEngine
    {
        get => _searchEngine;
        set => this.RaiseAndSetIfChanged(ref _searchEngine, value);
    }
    
    public SettingsViewModel()
    {
        SearchEngine = SearchEngine.Custom;
    }
}

This is the View.axaml.cs

public partial class SettingsView : AppWindow
{
    public SettingsView()
    {
        InitializeComponent();
        
        TitleBar.ExtendsContentIntoTitleBar = true;
        TitleBar.TitleBarHitTestType = TitleBarHitTestType.Complex;
    }
}

This is the View.axaml

<Window 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:ui="using:FluentAvalonia.UI.Controls"
        xmlns:animeArchiveHandlerGui="clr-namespace:Anime_Archive_Handler_GUI"
        xmlns:viewModels="clr-namespace:Anime_Archive_Handler_GUI.ViewModels"
        xmlns:converters="clr-namespace:Anime_Archive_Handler_GUI.Converters"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="Anime_Archive_Handler_GUI.Views.SettingsView"
        x:DataType="viewModels:SettingsViewModel"
        Title="Settings">
    
    <Window.Resources>
        <converters:EnumToBooleanConverter x:Key="EnumToBooleanConverter" />
    </Window.Resources>
    
    <Design.DataContext>
        <viewModels:SettingsViewModel />
    </Design.DataContext>
    
    <Grid RowDefinitions="32,Auto,*" Background="{StaticResource BackgroundColor}">
        <StackPanel Grid.Row="0" Orientation="Horizontal">
            <ui:SymbolIcon Symbol="Settings" />
            <TextBlock Text="Settings" VerticalAlignment="Center" Margin="10 0" />
        </StackPanel>
        <StackPanel Grid.Row="1" Orientation="Horizontal">
            <TabStrip>
                <TabItem Content="General" />
                <TabItem Content="Advanced" /> 
                <TabItem Content="Media" /> 
                <TabItem Content="Addons" /> 
                <TabItem Content="Experimental" /> 
            </TabStrip>
        </StackPanel>
        <StackPanel Grid.Row="2">
            <TextBlock Text="Search Engine" />
            <Grid>
                <RadioButton Content="Custom" GroupName="Search Engine" IsChecked="{Binding SearchEngine, Converter={StaticResource EnumToBooleanConverter}, ConverterParameter={x:Static animeArchiveHandlerGui:SearchEngine.Custom}}"/>
                <RadioButton Content="Lucene" GroupName="Search Engine" IsChecked="{Binding SearchEngine, Converter={StaticResource EnumToBooleanConverter}, ConverterParameter={x:Static animeArchiveHandlerGui:SearchEngine.Lucene}}"/>
                <RadioButton Content="Meilisearch" GroupName="Search Engine" IsChecked="{Binding SearchEngine, Converter={StaticResource EnumToBooleanConverter}, ConverterParameter={x:Static animeArchiveHandlerGui:SearchEngine.Meilisearch}}"/>
            </Grid>
        </StackPanel>
    </Grid>
</Window>

And this is how I am instantiating the window

case "PreferencesButton":
                new SettingsView {DataContext = new SettingsViewModel()}.Show();

Any help would be appreciated since I've been looking for an hour now and can seem to find the issue :)

[SirZeeno]

it was the tabitem using the content instead of header. I was tired from working on it for hours and didn't see it until I got some rest and a clear mind.

[SwiftExtender]

@SirZeeno did you find a solution?

[SirZeeno]

Yes, my solution was outlined in my comment that I forgot to mark as the answer, but I don't think this helps in your situation because it was an issue unrelated to what the error was telling me, and I was too tired to see it.