Skip to content

Fixed [ObservableProperty] for fields named "value" #4219

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Sep 2, 2021
Merged

Fixed [ObservableProperty] for fields named "value" #4219

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 14 additions & 6 deletions Microsoft.Toolkit.Mvvm.SourceGenerators/ComponentModel/ObservablePropertyGenerator.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,14 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(
}
}

// In case the backing field is exactly named "value", we need to add the "this." prefix to ensure that comparisons and assignments
// with it in the generated setter body are executed correctly and without conflicts with the implicit value parameter.
ExpressionSyntax fieldExpression = fieldSymbol.Name switch
{
"value" => MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, ThisExpression(), IdentifierName("value")),
string name => IdentifierName(name)
};

BlockSyntax setterBlock;

if (validationAttributes.Count > 0)
Expand All @@ -263,10 +271,10 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(

// Generate the inner setter block as follows:
//
// if (!global::System.Collections.Generic.EqualityComparer<<FIELD_TYPE>>.Default.Equals(<FIELD_NAME>, value))
// if (!global::System.Collections.Generic.EqualityComparer<<FIELD_TYPE>>.Default.Equals(this.<FIELD_NAME>, value))
// {
// OnPropertyChanging(global::Microsoft.Toolkit.Mvvm.ComponentModel.__Internals.__KnownINotifyPropertyChangedOrChangingArgs.PropertyNamePropertyChangingEventArgs); // Optional
// <FIELD_NAME> = value;
// this.<FIELD_NAME> = value;
// OnPropertyChanged(global::Microsoft.Toolkit.Mvvm.ComponentModel.__Internals.__KnownINotifyPropertyChangedOrChangingArgs.PropertyNamePropertyChangedEventArgs);
// ValidateProperty(value, <PROPERTY_NAME>);
// OnPropertyChanged(global::Microsoft.Toolkit.Mvvm.ComponentModel.__Internals.__KnownINotifyPropertyChangedOrChangingArgs.Property1PropertyChangedEventArgs); // Optional
Expand All @@ -291,7 +299,7 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(
IdentifierName("Default")),
IdentifierName("Equals")))
.AddArgumentListArguments(
Argument(IdentifierName(fieldSymbol.Name)),
Argument(fieldExpression),
Argument(IdentifierName("value")))),
Block(
ExpressionStatement(
Expand All @@ -303,7 +311,7 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(
ExpressionStatement(
AssignmentExpression(
SyntaxKind.SimpleAssignmentExpression,
IdentifierName(fieldSymbol.Name),
fieldExpression,
IdentifierName("value"))),
ExpressionStatement(
InvocationExpression(IdentifierName("OnPropertyChanged"))
Expand Down Expand Up @@ -346,7 +354,7 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(
ExpressionStatement(
AssignmentExpression(
SyntaxKind.SimpleAssignmentExpression,
IdentifierName(fieldSymbol.Name),
fieldExpression,
IdentifierName("value"))),
ExpressionStatement(
InvocationExpression(IdentifierName("OnPropertyChanged"))
Expand Down Expand Up @@ -384,7 +392,7 @@ private static PropertyDeclarationSyntax CreatePropertyDeclaration(
IdentifierName("Default")),
IdentifierName("Equals")))
.AddArgumentListArguments(
Argument(IdentifierName(fieldSymbol.Name)),
Argument(fieldExpression),
Argument(IdentifierName("value")))),
updateAndNotificationBlock));
}
Expand Down
50 changes: 50 additions & 0 deletions UnitTests/UnitTests.NetCore/Mvvm/Test_ObservablePropertyAttribute.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,42 @@ public void Test_ValidationAttributes()
Assert.AreEqual(testAttribute.Animal, Animal.Llama);
}

// See https://github.com/CommunityToolkit/WindowsCommunityToolkit/issues/4216
[TestCategory("Mvvm")]
[TestMethod]
public void Test_ObservablePropertyWithValueNamedField()
{
var model = new ModelWithValueProperty();

List<string?> propertyNames = new();

model.PropertyChanged += (s, e) => propertyNames.Add(e.PropertyName);

model.Value = "Hello world";

Assert.AreEqual(model.Value, "Hello world");

CollectionAssert.AreEqual(new[] { nameof(model.Value) }, propertyNames);
}

// See https://github.com/CommunityToolkit/WindowsCommunityToolkit/issues/4216
[TestCategory("Mvvm")]
[TestMethod]
public void Test_ObservablePropertyWithValueNamedField_WithValidationAttributes()
{
var model = new ModelWithValuePropertyWithValidation();

List<string?> propertyNames = new();

model.PropertyChanged += (s, e) => propertyNames.Add(e.PropertyName);

model.Value = "Hello world";

Assert.AreEqual(model.Value, "Hello world");

CollectionAssert.AreEqual(new[] { nameof(model.Value) }, propertyNames);
}

public partial class SampleModel : ObservableObject
{
/// <summary>
Expand Down Expand Up @@ -195,5 +231,19 @@ public enum Animal
Dog,
Llama
}

public partial class ModelWithValueProperty : ObservableObject
{
[ObservableProperty]
private string value;
}

public partial class ModelWithValuePropertyWithValidation : ObservableValidator
{
[ObservableProperty]
[Required]
[MinLength(5)]
private string value;
}
}
}