x:Bind in resource dictionary is not supported #13550
Description
In WinUI and UWP, you can create a resource dictionary with a code-behind class, which then allows you to use x:Bind inside that resource dictionary. This works fine for WinUI when using Uno, but when I try this with a WASM head I get the following error:
1>CSC : error UXAML0001: Unable to find x:Class on the top level element
Does anyone know how to resolve this error? Or is it just impossible to use x:Bind from a Resource Dictionary for a WASM head?
As an example, I created a small project to demonstrate this.
App.xaml:
<Application
x:Class="UnoResourceCodeBehind.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UnoResourceCodeBehind">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
<!-- Add resource dictionaries here -->
<local:ResourceDictionary1 xmlns="using:UnoResourceCodeBehind"/>
</ResourceDictionary.MergedDictionaries>
<!-- Add resources here -->
</ResourceDictionary>
</Application.Resources>
</Application>
MainPage.xaml:
<Page
x:Class="UnoResourceCodeBehind.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UnoResourceCodeBehind"
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>
<local:MyControl Style="{StaticResource MyStyle}"/>
</Grid>
</Page>
MyControl.cs:
using Microsoft.UI.Xaml.Controls;
using System;
using System.Collections.Generic;
using System.Text;
namespace UnoResourceCodeBehind
{
internal class MyControl : Control
{
public string GetText() => "text from control";
}
}
ResourceDictionary1.xaml:
<ResourceDictionary x:Class="UnoResourceCodeBehind.ResourceDictionary1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:UnoResourceCodeBehind">
<Style x:Name="MyStyle" TargetType="local:MyControl">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:MyControl">
<Grid>
<TextBlock Text="{x:Bind GetText()}"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
ResourceDictionary1.xaml.cs:
using Microsoft.UI.Xaml;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace UnoResourceCodeBehind
{
partial class ResourceDictionary1 : ResourceDictionary
{
public ResourceDictionary1()
{
this.InitializeComponent();
}
}
}
This is the build error I get when building for WASM:
1>CSC : error UXAML0001: Unable to find x:Class on the top level element
1>C:\Users\user1\source\repos\UnoResourceCodeBehind\UnoResourceCodeBehind\UnoResourceCodeBehind.Shared\ResourceDictionary1.xaml(10,22,10,22): error UXAML0001: An error was found in Grid
1>CSC : error UXAML0001: Processing failed for file C:\Users\user1\source\repos\UnoResourceCodeBehind\UnoResourceCodeBehind\UnoResourceCodeBehind.Shared\ResourceDictionary1.xaml (Uno.UI.SourceGenerators.XamlGenerator.XamlParsingException: An error was found in Grid ---> System.Exception: Unable to find x:Class on the top level element
1>C:\Users\user1\source\repos\UnoResourceCodeBehind\UnoResourceCodeBehind\UnoResourceCodeBehind.Shared\MainPage.xaml.cs(27,18,27,37): error CS1061: 'MainPage' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'MainPage' could be found (are you missing a using directive or an assembly reference?)
1>C:\Users\user1\source\repos\UnoResourceCodeBehind\UnoResourceCodeBehind\UnoResourceCodeBehind.Shared\ResourceDictionary1.xaml.cs(14,18,14,37): error CS1061: 'ResourceDictionary1' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'ResourceDictionary1' could be found (are you missing a using directive or an assembly reference?)
1>C:\Users\user1\source\repos\UnoResourceCodeBehind\UnoResourceCodeBehind\UnoResourceCodeBehind.Shared\App.xaml.cs(26,18,26,37): error CS1061: 'App' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'App' could be found (are you missing a using directive or an assembly reference?)
1>Done building project "UnoResourceCodeBehind.Wasm.csproj" -- FAILED.
My project is targeting .NET 7, btw.
Originally posted by @andrewkdci in #13545