fix: Properly generate code for items in custom dictionary

src/SamplesApp/SamplesApp.Shared/App.xaml

@@ -4,6 +4,7 @@
 			 xmlns:xamarin="http://nventive.com/xamarin"
 			 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 			 xmlns:ios="http://nventive.com/ios"
+			 xmlns:local="using:SamplesApp"
 			 xmlns:toolkit="using:Uno.UI.Toolkit"
 			 mc:Ignorable="ios"
 			 RequestedTheme="Light">
@@ -33,6 +34,12 @@
 				<MapResources xmlns="using:Uno.UI.Maps"/>
 			</ResourceDictionary.MergedDictionaries>
 
+			 <local:StringToStyleDictionary x:Key="MyResource">
+                <Style x:Key="MyStyle" TargetType="Button">
+
+                </Style>
+            </local:StringToStyleDictionary>
+
 			<SolidColorBrush x:Key="GlobalStaticResource_Test01"
 							 Color="Purple" />
 

src/SamplesApp/SamplesApp.Shared/SamplesApp.Shared.projitems

@@ -27,6 +27,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Samples\UnitTests\UnitTestsPage.xaml.cs">
       <DependentUpon>UnitTestsPage.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)StringToStyleDictionary.cs" />
   </ItemGroup>
   <ItemGroup>
     <Page Include="$(MSBuildThisFileDirectory)MainPage.xaml">
@@ -81,4 +82,4 @@
   <ItemGroup>
     <Folder Include="$(MSBuildThisFileDirectory)Embedded\SubFolder1\SubFolder2\" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>

src/SamplesApp/SamplesApp.Shared/StringToStyleDictionary.cs

+using System.Collections.Generic;
+using Windows.UI.Xaml;
+
+namespace SamplesApp;
+
+class StringToStyleDictionary : Dictionary<string, Style>
+{
+}

src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs

@@ -3313,6 +3313,11 @@ namespace Uno.UI.SourceGenerators.XamlGenerator
 									writer.AppendLineIndented($"{closureName}.Add(");
 									using (writer.Indent())
 									{
+										if (objectDefinitionType?.AllInterfaces.Any(i => i.OriginalDefinition.Equals(Generation.IDictionaryOfTKeySymbol.Value, SymbolEqualityComparer.Default)) == true &&
+											GetDictionaryResourceKey(item) is string dictionaryKey)
+										{
+											writer.AppendLineIndented($"\"{dictionaryKey}\",");
+										}
 										BuildChild(writer, member, item);
 									}
 									writer.AppendLineIndented(");");