for some reason the XAML source code (see below) is not discoverable by the Integrated Development Environment (IDE).
<Page
x:Class="Network.Interface"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:Network"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<muxc:TabView>
<muxc:TabView.TabItems>
<muxc:TabViewItem />
</muxc:TabView.TabItems>
</muxc:TabView>
</Grid>
</Page>
IDE - JetBrains Rider 2021.1.2
If you want to use muxc:TabView on xaml page correctly, please refer to the following steps.
1.Download the corresponding package through Package Manager. Steps: Reference->Manage NuGet Packages->Browse->Search Microsoft.UI.Xaml.Controls and install it.
2.Add xmlns:muxc="using:Microsoft.UI.Xaml.Controls" to page element, as follows:
<Page
...
xmlns:muxc="using:Microsoft.UI.Xaml.Controls"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
...
</Page>