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Merge pull request #2251 from Cratis:fix/auto-map-children
Fix/auto-map-children
2 parents 02783c0 + 566fd69 commit c8e92a5

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‎Documentation/projections/model-bound/children.md‎

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@@ -31,6 +31,59 @@ public record LineItem(
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- **key** (optional): Property on the event that identifies the child. Defaults to `EventSourceId`
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- **identifiedBy** (optional): Property on the child model that identifies it. Defaults to `Id`
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- **parentKey** (optional): Property that identifies the parent. Defaults to `EventSourceId`
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- **autoMap** (optional): Whether to automatically map matching properties from the event to the child model. Defaults to `true`
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### Auto-Mapping
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By default, `ChildrenFrom` automatically maps properties from the event to the child model when property names match. This behavior is similar to the `FromEvent` attribute:
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```csharp
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public record Order(
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[Key]
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Guid OrderId,
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[ChildrenFrom<LineItemAdded>(key: nameof(LineItemAdded.ItemId))]
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IEnumerable<LineItem> Items);
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public record LineItem(
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[Key] Guid Id,
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string ProductName, // Automatically mapped from LineItemAdded.ProductName
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int Quantity, // Automatically mapped from LineItemAdded.Quantity
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decimal Price); // Automatically mapped from LineItemAdded.Price
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[EventType]
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public record LineItemAdded(
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Guid ItemId,
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string ProductName,
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int Quantity,
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decimal Price);
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```
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You can disable auto-mapping if you want to control property mapping explicitly:
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```csharp
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public record Order(
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[Key]
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Guid OrderId,
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[ChildrenFrom<LineItemAdded>(
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key: nameof(LineItemAdded.ItemId),
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autoMap: false)]
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IEnumerable<LineItem> Items);
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public record LineItem(
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[Key] Guid Id,
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// Now you must use SetFrom for each property
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[SetFrom<LineItemAdded>(nameof(LineItemAdded.ProductName))]
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string ProductName,
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[SetFrom<LineItemAdded>(nameof(LineItemAdded.Quantity))]
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int Quantity,
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[SetFrom<LineItemAdded>(nameof(LineItemAdded.Price))]
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decimal Price);
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```
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## Recursive Attribute Processing
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‎Source/Clients/DotNET.Specs/Projections/ModelBound/for_ChildrenFromAttribute/when_creating_with_auto_map_explicitly_set_to_true.cs‎

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// Copyright (c) Cratis. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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namespace Cratis.Chronicle.Projections.ModelBound.for_ChildrenFromAttribute;
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public class when_creating_with_auto_map_explicitly_set_to_true : Specification
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{
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ChildrenFromAttribute<SomeEvent> _attribute;
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void Because() => _attribute = new ChildrenFromAttribute<SomeEvent>(autoMap: true);
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[Fact] void should_have_auto_map_set_to_true() => _attribute.AutoMap.ShouldBeTrue();
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}

‎Source/Clients/DotNET.Specs/Projections/ModelBound/for_ChildrenFromAttribute/when_creating_with_auto_map_set_to_false.cs‎

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// Copyright (c) Cratis. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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namespace Cratis.Chronicle.Projections.ModelBound.for_ChildrenFromAttribute;
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public class when_creating_with_auto_map_set_to_false : Specification
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{
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ChildrenFromAttribute<SomeEvent> _attribute;
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void Because() => _attribute = new ChildrenFromAttribute<SomeEvent>(autoMap: false);
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[Fact] void should_have_auto_map_set_to_false() => _attribute.AutoMap.ShouldBeFalse();
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}

‎Source/Clients/DotNET.Specs/Projections/ModelBound/for_ChildrenFromAttribute/when_creating_with_default_parameters.cs‎

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// Copyright (c) Cratis. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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#pragma warning disable SA1649 // File name should match first type name
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#pragma warning disable SA1402 // File may only contain a single type
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namespace Cratis.Chronicle.Projections.ModelBound.for_ChildrenFromAttribute;
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public class when_creating_with_default_parameters : Specification
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{
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ChildrenFromAttribute<SomeEvent> _attribute;
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void Because() => _attribute = new ChildrenFromAttribute<SomeEvent>();
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[Fact] void should_have_auto_map_set_to_true() => _attribute.AutoMap.ShouldBeTrue();
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}
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public record SomeEvent(Guid ItemId, string Name);

‎Source/Clients/DotNET.Specs/Projections/ModelBound/for_ModelBoundProjectionBuilder/when_building_model_with_children_from_with_auto_map.cs‎

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// Copyright (c) Cratis. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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#pragma warning disable SA1649 // File name should match first type name
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#pragma warning disable SA1402 // File may only contain a single type
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using Cratis.Chronicle.Contracts.Projections;
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using Cratis.Chronicle.Events;
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using Cratis.Chronicle.Keys;
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namespace Cratis.Chronicle.Projections.ModelBound.for_ModelBoundProjectionBuilder;
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public class when_building_model_with_children_from_with_auto_map : given.a_model_bound_projection_builder
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{
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ProjectionDefinition _result;
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void Establish()
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{
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event_types = new EventTypesForSpecifications([
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typeof(DebitAccountOpened),
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typeof(DepositToDebitAccountPerformed),
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typeof(WithdrawalFromDebitAccountPerformed),
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typeof(ItemAddedToCart),
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typeof(LineItemAdded)
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]);
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builder = new ModelBoundProjectionBuilder(naming_policy, event_types);
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}
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void Because() => _result = builder.Build(typeof(OrderWithAutoMappedChildren));
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[Fact] void should_return_definition() => _result.ShouldNotBeNull();
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[Fact] void should_have_children_definition() => _result.Children.Count.ShouldEqual(1);
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[Fact] void should_have_children_for_items() => _result.Children.Keys.ShouldContain(nameof(OrderWithAutoMappedChildren.Items));
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[Fact] void should_have_from_definition_for_line_item_added()
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{
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var eventType = event_types.GetEventTypeFor(typeof(LineItemAdded)).ToContract();
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var childrenDef = _result.Children[nameof(OrderWithAutoMappedChildren.Items)];
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childrenDef.From.Keys.ShouldContain(et => et.IsEqual(eventType));
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}
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[Fact] void should_auto_map_product_name()
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{
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var eventType = event_types.GetEventTypeFor(typeof(LineItemAdded)).ToContract();
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var childrenDef = _result.Children[nameof(OrderWithAutoMappedChildren.Items)];
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var fromDef = childrenDef.From.Single(kvp => kvp.Key.IsEqual(eventType)).Value;
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fromDef.Properties.Keys.ShouldContain(nameof(OrderLineItem.ProductName));
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}
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[Fact] void should_auto_map_quantity()
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{
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var eventType = event_types.GetEventTypeFor(typeof(LineItemAdded)).ToContract();
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var childrenDef = _result.Children[nameof(OrderWithAutoMappedChildren.Items)];
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var fromDef = childrenDef.From.Single(kvp => kvp.Key.IsEqual(eventType)).Value;
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fromDef.Properties.Keys.ShouldContain(nameof(OrderLineItem.Quantity));
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}
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[Fact] void should_auto_map_price()
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{
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var eventType = event_types.GetEventTypeFor(typeof(LineItemAdded)).ToContract();
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var childrenDef = _result.Children[nameof(OrderWithAutoMappedChildren.Items)];
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var fromDef = childrenDef.From.Single(kvp => kvp.Key.IsEqual(eventType)).Value;
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fromDef.Properties.Keys.ShouldContain(nameof(OrderLineItem.Price));
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}
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}
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[EventType]
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public record LineItemAdded(Guid ItemId, string ProductName, int Quantity, double Price);
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public record OrderLineItem([Key] Guid Id, string ProductName, int Quantity, double Price);
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public record OrderWithAutoMappedChildren(
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[Key] Guid Id,
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[ChildrenFrom<LineItemAdded>(key: nameof(LineItemAdded.ItemId))] IEnumerable<OrderLineItem> Items);

‎Source/Clients/DotNET.Specs/Projections/ModelBound/for_ModelBoundProjectionBuilder/when_building_model_with_children_from_with_auto_map_disabled.cs‎

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// Copyright (c) Cratis. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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#pragma warning disable SA1649 // File name should match first type name
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#pragma warning disable SA1402 // File may only contain a single type
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using Cratis.Chronicle.Contracts.Projections;
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using Cratis.Chronicle.Events;
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using Cratis.Chronicle.Keys;
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namespace Cratis.Chronicle.Projections.ModelBound.for_ModelBoundProjectionBuilder;
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public class when_building_model_with_children_from_with_auto_map_disabled : given.a_model_bound_projection_builder
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{
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ProjectionDefinition _result;
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void Establish()
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{
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event_types = new EventTypesForSpecifications([
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typeof(DebitAccountOpened),
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typeof(DepositToDebitAccountPerformed),
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typeof(WithdrawalFromDebitAccountPerformed),
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typeof(ItemAddedToCart),
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typeof(ProductItemAdded)
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]);
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builder = new ModelBoundProjectionBuilder(naming_policy, event_types);
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}
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void Because() => _result = builder.Build(typeof(OrderWithExplicitMappedChildren));
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[Fact] void should_return_definition() => _result.ShouldNotBeNull();
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[Fact] void should_have_children_definition() => _result.Children.Count.ShouldEqual(1);
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[Fact] void should_not_auto_map_properties()
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{
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var eventType = event_types.GetEventTypeFor(typeof(ProductItemAdded)).ToContract();
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var childrenDef = _result.Children[nameof(OrderWithExplicitMappedChildren.Items)];
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var fromDef = childrenDef.From.Single(kvp => kvp.Key.IsEqual(eventType)).Value;
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// With autoMap disabled, properties should not be automatically mapped
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// Only the Id should be empty since we don't have explicit SetFrom attributes
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fromDef.Properties.Count.ShouldEqual(0);
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}
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}
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[EventType]
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public record ProductItemAdded(Guid ItemId, string ProductName, int Quantity, double Price);
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public record ProductLineItem([Key] Guid Id, string ProductName, int Quantity, double Price);
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public record OrderWithExplicitMappedChildren(
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[Key] Guid Id,
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[ChildrenFrom<ProductItemAdded>(key: nameof(ProductItemAdded.ItemId), autoMap: false)]
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IEnumerable<ProductLineItem> Items);

‎Source/Clients/DotNET/Projections/ModelBound/ChildrenDefinitionExtensions.cs‎

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var keyProperty = attr.GetType().GetProperty(nameof(ChildrenFromAttribute<object>.Key));
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var identifiedByProperty = attr.GetType().GetProperty(nameof(ChildrenFromAttribute<object>.IdentifiedBy));
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var parentKeyProperty = attr.GetType().GetProperty(nameof(ChildrenFromAttribute<object>.ParentKey));
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var autoMapProperty = attr.GetType().GetProperty(nameof(ChildrenFromAttribute<object>.AutoMap));
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var key = keyProperty?.GetValue(attr) as string ?? WellKnownExpressions.EventSourceId;
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var identifiedBy = identifiedByProperty?.GetValue(attr) as string ?? WellKnownExpressions.Id;
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var parentKey = parentKeyProperty?.GetValue(attr) as string ?? WellKnownExpressions.EventSourceId;
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var autoMap = autoMapProperty?.GetValue(attr) as bool? ?? true;
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if (!definition.Children.TryGetValue(propertyName, out var childrenDef))
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{
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var childType = GetChildType(memberType);
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if (childType is not null)
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{
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// If autoMap is enabled, map matching properties from event to child model
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if (autoMap)
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{
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var fromDefinition = childrenDef.From[eventTypeId];
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fromDefinition.AutoMapMatchingProperties(namingPolicy, eventType, childType);
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}
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foreach (var childProperty in childType.GetProperties(BindingFlags.Public | BindingFlags.Instance))
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{
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processMember(childProperty, definition, [], false, childrenDef);

‎Source/Clients/DotNET/Projections/ModelBound/ChildrenFromAttribute.cs‎

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/// <param name="key">Optional property name on the event that identifies the child. Defaults to WellKnownExpressions.EventSourceId.</param>
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/// <param name="identifiedBy">Optional property name on the child model that identifies it. Defaults to WellKnownExpressions.Id.</param>
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/// <param name="parentKey">Optional property name that identifies the parent. Defaults to WellKnownExpressions.EventSourceId.</param>
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/// <param name="autoMap">Whether to automatically map matching properties from the event to the child model. Defaults to true.</param>
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[AttributeUsage(AttributeTargets.Property | AttributeTargets.Parameter, AllowMultiple = true)]
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public sealed class ChildrenFromAttribute<TEvent>(
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string? key = default,
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string? identifiedBy = default,
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string? parentKey = default) : Attribute, IProjectionAnnotation, IChildrenFromAttribute
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string? parentKey = default,
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bool autoMap = true) : Attribute, IProjectionAnnotation, IChildrenFromAttribute
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{
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/// <inheritdoc/>
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public Type EventType => typeof(TEvent);
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/// <inheritdoc/>
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public string IdentifiedBy { get; } = identifiedBy ?? WellKnownExpressions.Id;
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/// <inheritdoc/>
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public bool AutoMap { get; } = autoMap;
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}

‎Source/Clients/DotNET/Projections/ModelBound/FromDefinitionExtensions.cs‎

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fromDefinition.Properties[propertyName] = $"{WellKnownExpressions.EventContext}({convertedContextPropertyName})";
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}
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/// <summary>
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/// Auto-maps properties from event type to model type by matching property names.
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/// </summary>
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/// <param name="fromDefinition">The FromDefinition to add property mappings to.</param>
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/// <param name="namingPolicy">The naming policy for converting property names.</param>
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/// <param name="eventType">The event type to map from.</param>
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/// <param name="modelType">The model type to map to.</param>
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internal static void AutoMapMatchingProperties(this FromDefinition fromDefinition, INamingPolicy namingPolicy, Type eventType, Type modelType)
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{
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foreach (var modelProperty in modelType.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance))
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{
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var eventProperty = eventType.GetProperty(modelProperty.Name);
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if (eventProperty is not null)
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{
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var modelPropertyPath = new PropertyPath(modelProperty.Name);
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var modelPropertyName = namingPolicy.GetPropertyName(modelPropertyPath);
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var eventPropertyPath = new PropertyPath(eventProperty.Name);
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fromDefinition.Properties[modelPropertyName] = namingPolicy.GetPropertyName(eventPropertyPath);
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}
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}
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}
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static FromDefinition GetOrCreateFromDefinition(this IDictionary<EventType, FromDefinition> targetFrom, EventType eventTypeId)
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{
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if (!targetFrom.TryGetValue(eventTypeId, out var fromDefinition))

‎Source/Clients/DotNET/Projections/ModelBound/IAddFromAttribute.cs‎

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/// <summary>
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/// Defines an attribute that indicates that a property value should be added from an event property.
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/// </summary>
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public interface IAddFromAttribute : IEventBoundAttribute
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{
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/// <summary>
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/// Gets the name of the property on the event.
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/// </summary>
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string? EventPropertyName { get; }
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}
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public interface IAddFromAttribute : IEventBoundAttribute, ICanMapToEventProperty;

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