Add compile-time property initializer for default values in BindableProperty source generaor

src/CommunityToolkit.Maui.SourceGenerators.UnitTests/BindablePropertyAttributeSourceGeneratorTests/BindablePropertyAttributeSourceGenerator_CommonUsageTests.cs

@@ -598,8 +598,8 @@ public partial class {{defaultTestClassName}}
 			    /// <summary>
 			    /// BindableProperty for the <see cref = "Text"/> property.
 			    /// </summary>
-			    public static readonly global::Microsoft.Maui.Controls.BindableProperty TextProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Text", typeof(string), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}), null, (Microsoft.Maui.Controls.BindingMode)0, null, null, null, null, __{{defaultTestClassName}}BindablePropertyInitHelpers.CreateDefaultText);
-			    public partial string Text { get => __{{defaultTestClassName}}BindablePropertyInitHelpers.IsInitializingText ? field : (string)GetValue(TextProperty); set => SetValue(TextProperty, value); }
+			    public static readonly global::Microsoft.Maui.Controls.BindableProperty TextProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Text", typeof(string), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}), "Initial Value", (Microsoft.Maui.Controls.BindingMode)0, null, null, null, null, null);
+			    public partial string Text { get => false ? field : (string)GetValue(TextProperty); set => SetValue(TextProperty, value); }
 
 			    /// <summary>
 			    /// BindableProperty for the <see cref = "CustomDuration"/> property.
@@ -610,20 +610,11 @@ public partial class {{defaultTestClassName}}
 
 			file static class __{{defaultTestClassName}}BindablePropertyInitHelpers
 			{
-			    public static volatile bool IsInitializingText = false;
-			    public static object CreateDefaultText(global::Microsoft.Maui.Controls.BindableObject bindable)
-			    {
-			        IsInitializingText = true;
-			        var defaultValue = ((TestView)bindable).Text;
-			        IsInitializingText = false;
-			        return defaultValue;
-			    }
-
 			    public static volatile bool IsInitializingCustomDuration = false;
 			    public static object CreateDefaultCustomDuration(global::Microsoft.Maui.Controls.BindableObject bindable)
 			    {
 			        IsInitializingCustomDuration = true;
-			        var defaultValue = ((TestView)bindable).CustomDuration;
+			        var defaultValue = (({{defaultTestClassName}})bindable).CustomDuration;
 			        IsInitializingCustomDuration = false;
 			        return defaultValue;
 			    }

src/CommunityToolkit.Maui.SourceGenerators.UnitTests/BindablePropertyAttributeSourceGeneratorTests/BindablePropertyAttributeSourceGenerator_IntegrationTests.cs

@@ -162,21 +162,8 @@ public partial class {{defaultTestClassName}}<T, U>
 		    /// <summary>
 		    /// BindableProperty for the <see cref = "Value"/> property.
 		    /// </summary>
-		    public static readonly global::Microsoft.Maui.Controls.BindableProperty ValueProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Value", typeof(T), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}<T, U>), null, (Microsoft.Maui.Controls.BindingMode)0, null, null, null, null, __{{defaultTestClassName}}BindablePropertyInitHelpers.CreateDefaultValue);
-		    public partial T? Value { get => __{{defaultTestClassName}}BindablePropertyInitHelpers.IsInitializingValue ? field : (T? )GetValue(ValueProperty); set => SetValue(ValueProperty, value); }
-
-		    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
-		    private static class __{{defaultTestClassName}}BindablePropertyInitHelpers
-		    {
-		        public static volatile bool IsInitializingValue = false;
-		        public static object CreateDefaultValue(global::Microsoft.Maui.Controls.BindableObject bindable)
-		        {
-		            IsInitializingValue = true;
-		            var defaultValue = (({{defaultTestClassName}}<T, U>)bindable).Value;
-		            IsInitializingValue = false;
-		            return defaultValue;
-		        }
-		    }
+		    public static readonly global::Microsoft.Maui.Controls.BindableProperty ValueProperty = global::Microsoft.Maui.Controls.BindableProperty.Create("Value", typeof(T), typeof({{defaultTestNamespace}}.{{defaultTestClassName}}<T, U>), default(T), (Microsoft.Maui.Controls.BindingMode)0, null, null, null, null, null);
+		    public partial T? Value { get => false ? field : (T? )GetValue(ValueProperty); set => SetValue(ValueProperty, value); }
 		}
 		""";
 

src/CommunityToolkit.Maui.SourceGenerators/Generators/BindablePropertyAttributeSourceGenerator.cs

@@ -237,7 +237,7 @@ static void GenerateReadOnlyBindableProperty(StringBuilder sb, in BindableProper
 			.Append(GetFormattedReturnType(nonNullableReturnType))
 			.Append("), typeof(")
 			.Append(info.DeclaringType)
-			.Append("), null, ")
+			.Append("), ").Append(info.ResolvedInitializerExpression ?? "null").Append(", ")
 			.Append(info.DefaultBindingMode)
 			.Append(", ")
 			.Append(info.ValidateValueMethodName)
@@ -304,7 +304,7 @@ static void GenerateBindableProperty(StringBuilder sb, in BindablePropertyModel
 			.Append(GetFormattedReturnType(nonNullableReturnType))
 			.Append("), typeof(")
 			.Append(info.DeclaringType)
-			.Append("), null, ")
+			.Append("), ").Append(info.ResolvedInitializerExpression ?? "null").Append(", ")
 			.Append(info.DefaultBindingMode)
 			.Append(", ")
 			.Append(info.ValidateValueMethodName)
@@ -408,8 +408,16 @@ static BindablePropertySemanticValues SemanticTransform(GeneratorAttributeSyntax
 
 		var propertyAccessibility = GetPropertyAccessibility(propertySymbol);
 
+		// Resolve initializer expression to a fully qualified string for use as defaultValue
+		string? resolvedInitializer = null;
+		if (hasInitializer && propertyDeclarationSyntax.Initializer is not null)
+		{
+			resolvedInitializer = Helpers.InitializerExpressionResolver.TryResolve(
+				propertyDeclarationSyntax.Initializer.Value, semanticModel);
+		}
+
 		var attributeData = context.Attributes[0];
-		bindablePropertyModels[0] = CreateBindablePropertyModel(attributeData, propertySymbol.ContainingType, propertySymbol.Name, returnType, doesContainNewKeyword, isReadOnlyBindableProperty, setterAccessibility, hasInitializer, propertyAccessibility);
+		bindablePropertyModels[0] = CreateBindablePropertyModel(attributeData, propertySymbol.ContainingType, propertySymbol.Name, returnType, doesContainNewKeyword, isReadOnlyBindableProperty, setterAccessibility, hasInitializer, propertyAccessibility, resolvedInitializer);
 
 		return new(propertyInfo, ImmutableArray.Create(bindablePropertyModels));
 	}
@@ -517,7 +525,7 @@ static string GetGenericTypeParameters(INamedTypeSymbol typeSymbol)
 		return sb.ToString();
 	}
 
-	static BindablePropertyModel CreateBindablePropertyModel(in AttributeData attributeData, in INamedTypeSymbol declaringType, in string propertyName, in ITypeSymbol returnType, in bool doesContainNewKeyword, in bool isReadOnly, in string? setterAccessibility, in bool hasInitializer, in string? propertyAccessibility)
+	static BindablePropertyModel CreateBindablePropertyModel(in AttributeData attributeData, in INamedTypeSymbol declaringType, in string propertyName, in ITypeSymbol returnType, in bool doesContainNewKeyword, in bool isReadOnly, in string? setterAccessibility, in bool hasInitializer, in string? propertyAccessibility, in string? resolvedInitializerExpression)
 	{
 		if (attributeData.AttributeClass is null)
 		{
@@ -532,7 +540,10 @@ static BindablePropertyModel CreateBindablePropertyModel(in AttributeData attrib
 		var validateValueMethodName = attributeData.GetNamedMethodGroupArgumentsAttributeValueByNameAsString(nameof(BindablePropertyModel.ValidateValueMethodName));
 		var newKeywordText = doesContainNewKeyword ? "new " : string.Empty;
 
-		return new BindablePropertyModel(propertyName, returnType, declaringType, defaultBindingMode, validateValueMethodName, propertyChangedMethodName, propertyChangingMethodName, coerceValueMethodName, defaultValueCreatorMethodName, newKeywordText, isReadOnly, setterAccessibility, hasInitializer, propertyAccessibility);
+		// Only use the resolved initializer when there's no explicit DefaultValueCreatorMethodName
+		var effectiveResolvedInitializer = defaultValueCreatorMethodName is "null" ? resolvedInitializerExpression : null;
+
+		return new BindablePropertyModel(propertyName, returnType, declaringType, defaultBindingMode, validateValueMethodName, propertyChangedMethodName, propertyChangingMethodName, coerceValueMethodName, defaultValueCreatorMethodName, newKeywordText, isReadOnly, setterAccessibility, hasInitializer, propertyAccessibility, effectiveResolvedInitializer);
 	}
 
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]