How to preview an ItemTemplate in the XAML designer - visual-studio

Question

Say I have a simple ItemTemplate for a ListView
<ListView ItemsSource="{x:Bind ListItems}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:TextItem">
<TextBlock Text="{x:Bind Item}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
MainPage.xaml
When I run the app, I get a ListView populated with TextBlocks - one for each item in ListItems (which is a behind defined variable). However, in the XAML designer, I see nothing.
So, is there a way to preview the ItemTemplate/DataTemplate in the XAML designer, with a set number of placeholder TextBlocks with placeholder text replacing the Text="{x:Bind Item}"? Or just preview a single TextBlock?
This is not a duplicate of
Design View of a DataTemplate in a ResourceDictionary in Visual Studio - because I can't use Blend. Everything I've looked up that says use Blend in a certain way merely gives me the message 'This feature is not available for projects targeting "Windows 10 Fall Creators Update (10.0; Build 16299)"'
Can I preview my DataTemplate(s) in my collection-based controls in the designer? - well, perhaps it is, but I don't understand the accepted answer, which is now several years old. An answer containing an example tailored to my question would be really helpful.

Answer 1

Microsoft actually posted a (semi helpful) tutorial on this in April of this year: link
Requirements
Whatever you want to display, you will need this at the top of your XAML code (should be there by default if you created the page using VS's templates):
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
A simple list of strings
For something simple like a list of strings, something like this will work just fine (taken from the above mentioned MSDN page):
<ListView>
<d:ListView.Items>
<system:String>Item One</system:String>
<system:String>Item Two</system:String>
<system:String>Item Three</system:String>
</d:ListView.Items>
</ListView>
Display something more complex
If you want to use a data source from somewhere else in your code, it gets a little more ugly:
First you need to set your data context (usually done at the page level, but you can also add it just on the element where you want to use it):
d:DataContext="{d:DesignInstance
yournamespace:YourDataSourceClass,
IsDesignTimeCreatable=True}"
And on the ListView add:
d:ItemsSource="{Binding data}"
If you are using an ItemTemplate, you will need to add "d:" variants for everything you want to pull from your data source.
Full example code:
XAML:
<Page
x:Class="exampleApp.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:exampleApp"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance local:DesignTimeData,
IsDesignTimeCreatable=True}"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<Grid>
<ListView ItemsSource="{x:Bind ListItems}" d:ItemsSource="{Binding DummyData}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:TextItem">
<TextBlock Text="{x:Bind Item}" d:Text="{Binding Item}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Grid>
</Page>
C#:
using System.Collections.ObjectModel;
using Windows.UI.Xaml.Controls;
namespace exampleApp {
public sealed partial class MainPage : Page {
public ObservableCollection<TextItem> ListItems;
public MainPage() {
this.InitializeComponent();
//populate you ListItems list
}
}
public class TextItem {
public string Item { get; set; }
}
public class DesignTimeData {
public ObservableCollection<TextItem> DummyData { get; set; } = new ObservableCollection<TextItem> {
new TextItem { Item = "foo" },
new TextItem { Item = "bar" },
new TextItem { Item = "bla" },
new TextItem { Item = "blubb" }
};
}
}
Remarks
It seems you have to use "Binding" rather than "x:Bind" for the design-time bindings. From what I understand, x:Bind works using code generated at compile time, which is not executed by the XAML designer
When you change your Binding declarations or data source code, you will have to recompile to see the changes in the designer. Other design changes will reflect in real time
Binding is more limited than x:Bind in some regards (notably you cannot bind to class methods using Binding, only x:Bind). Keep that in mind when writing your design-time data
Sadly some of the more convenient ways of getting design-time data into your app are WPF and Xamarin only (Blends' data window, data declared in XAML file, and especially auto-generated sample data)
(Everything was tested using Visual Studio 2019 version 16.10.3.)