private static void MakeWithBackingFieldNotify(DocumentEditor editor, PropertyDeclarationSyntax propertyDeclaration, IMethodSymbol invoker, SemanticModel semanticModel, CancellationToken cancellationToken)
{
var classDeclaration = propertyDeclaration.FirstAncestorOrSelf <ClassDeclarationSyntax>();
if (classDeclaration == null)
{
return;
}
if (IsSimpleAssignmentOnly(propertyDeclaration, out var setter, out var statement, out var assignment, out _))
{
var underscoreFields = CodeStyle.UnderscoreFields(semanticModel);
var property = semanticModel.GetDeclaredSymbolSafe(propertyDeclaration, cancellationToken);
var notifyStatement = SyntaxFactory
.ParseStatement(Snippet.OnPropertyChanged(invoker, property.Name, underscoreFields))
.WithLeadingTrivia(SyntaxFactory.ElasticMarker)
.WithTrailingTrivia(SyntaxFactory.ElasticMarker)
.WithSimplifiedNames()
.WithAdditionalAnnotations(Formatter.Annotation);
if (setter.ExpressionBody != null)
{
editor.ReplaceNode(
setter,
(x, _) =>
{
var old = (AccessorDeclarationSyntax)x;
return(old.WithBody(
SyntaxFactory.Block(
SyntaxFactory.ExpressionStatement(assignment),
notifyStatement))
.WithExpressionBody(null)
.WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.None)));
});
editor.FormatNode(propertyDeclaration);
}
else if (setter.Body != null)
{
editor.InsertAfter(statement, notifyStatement);
editor.FormatNode(propertyDeclaration);
}
}
}
private static void MakeNotify(DocumentEditor editor, ExpressionSyntax assignment, string propertyName, IMethodSymbol invoker, bool usesUnderscoreNames)
{
var snippet =
assignment.FirstAncestor <PropertyDeclarationSyntax>() is PropertyDeclarationSyntax
propertyDeclaration &&
propertyDeclaration.Identifier.ValueText == propertyName
? Snippet.OnPropertyChanged(invoker, propertyName, usesUnderscoreNames)
: Snippet.OnOtherPropertyChanged(invoker, propertyName, usesUnderscoreNames);
var onPropertyChanged = SyntaxFactory.ParseStatement(snippet)
.WithSimplifiedNames()
.WithLeadingElasticLineFeed()
.WithTrailingElasticLineFeed()
.WithAdditionalAnnotations(Formatter.Annotation);
if (assignment.Parent is AnonymousFunctionExpressionSyntax anonymousFunction)
{
if (anonymousFunction.Body is BlockSyntax block)
{
if (block.Statements.Count > 1)
{
var previousStatement = InsertAfter(block, block.Statements.Last(), invoker);
editor.InsertAfter(previousStatement, new[] { onPropertyChanged });
}
return;
}
var expressionStatement = (ExpressionStatementSyntax)editor.Generator.ExpressionStatement(anonymousFunction.Body);
var withStatements = editor.Generator.WithStatements(anonymousFunction, new[] { expressionStatement, onPropertyChanged });
editor.ReplaceNode(anonymousFunction, withStatements);
}
else if (assignment.Parent is ExpressionStatementSyntax assignStatement &&
assignStatement.Parent is BlockSyntax assignBlock)
{
var previousStatement = InsertAfter(assignBlock, assignStatement, invoker);
editor.InsertAfter(previousStatement, new[] { onPropertyChanged });
}
private static void MakeWithBackingFieldNotifyWhenValueChanges(DocumentEditor editor, PropertyDeclarationSyntax propertyDeclaration, IMethodSymbol invoker, SemanticModel semanticModel, CancellationToken cancellationToken)
{
var classDeclaration = propertyDeclaration.FirstAncestorOrSelf <ClassDeclarationSyntax>();
if (classDeclaration == null)
{
return;
}
if (propertyDeclaration.TryGetSetter(out var setter))
{
if (setter.ExpressionBody != null &&
IsSimpleAssignmentOnly(propertyDeclaration, out _, out _, out var assignment, out _))
{
var property = semanticModel.GetDeclaredSymbolSafe(propertyDeclaration, cancellationToken);
var underscoreFields = CodeStyle.UnderscoreFields(semanticModel);
var code = StringBuilderPool.Borrow()
.AppendLine($"public Type PropertyName")
.AppendLine("{")
.AppendLine($" get => {assignment.Left};")
.AppendLine()
.AppendLine(" set")
.AppendLine(" {")
.AppendLine($" if ({Snippet.EqualityCheck(property.Type, "value", assignment.Left.ToString(), semanticModel)})")
.AppendLine(" {")
.AppendLine($" return;")
.AppendLine(" }")
.AppendLine()
.AppendLine($" {assignment};")
.AppendLine($" {Snippet.OnPropertyChanged(invoker, property.Name, underscoreFields)}")
.AppendLine(" }")
.AppendLine("}")
.Return();
var template = ParseProperty(code);
editor.ReplaceNode(
setter,
(x, _) =>
{
var old = (AccessorDeclarationSyntax)x;
return(old.WithBody(template.Setter().Body)
.WithExpressionBody(null)
.WithSemicolonToken(SyntaxFactory.Token(SyntaxKind.None)));
});
editor.FormatNode(propertyDeclaration);
}
if (setter.Body?.Statements.Count == 1 &&
IsSimpleAssignmentOnly(propertyDeclaration, out _, out var statement, out assignment, out _))
{
var property = semanticModel.GetDeclaredSymbolSafe(propertyDeclaration, cancellationToken);
var code = StringBuilderPool.Borrow()
.AppendLine($" if ({Snippet.EqualityCheck(property.Type, "value", assignment.Left.ToString(), semanticModel)})")
.AppendLine(" {")
.AppendLine($" return;")
.AppendLine(" }")
.AppendLine()
.Return();
var ifStatement = SyntaxFactory.ParseStatement(code)
.WithSimplifiedNames()
.WithLeadingElasticLineFeed()
.WithTrailingElasticLineFeed()
.WithAdditionalAnnotations(Formatter.Annotation);
editor.InsertBefore(
statement,
ifStatement);
var underscoreFields = CodeStyle.UnderscoreFields(semanticModel);
var notifyStatement = SyntaxFactory
.ParseStatement(
Snippet.OnPropertyChanged(invoker, property.Name, underscoreFields))
.WithSimplifiedNames()
.WithLeadingElasticLineFeed()
.WithTrailingElasticLineFeed()
.WithAdditionalAnnotations(Formatter.Annotation);
editor.InsertAfter(statement, notifyStatement);
editor.FormatNode(propertyDeclaration);
}
}
}
/// <inheritdoc/>
public override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
var syntaxRoot = await context.Document.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken)
.ConfigureAwait(false);
foreach (var diagnostic in context.Diagnostics)
{
var token = syntaxRoot.FindToken(diagnostic.Location.SourceSpan.Start);
if (string.IsNullOrEmpty(token.ValueText))
{
continue;
}
var ifStatement = syntaxRoot.FindNode(diagnostic.Location.SourceSpan)
.FirstAncestorOrSelf <IfStatementSyntax>();
if (!IsIfReturn(ifStatement))
{
continue;
}
var setter = ifStatement.FirstAncestorOrSelf <AccessorDeclarationSyntax>();
if (setter?.IsKind(SyntaxKind.SetAccessorDeclaration) != true)
{
continue;
}
var propertyDeclaration = setter.FirstAncestorOrSelf <PropertyDeclarationSyntax>();
var property = semanticModel.GetDeclaredSymbolSafe(propertyDeclaration, context.CancellationToken);
if (property == null)
{
continue;
}
if (!Property.TryGetBackingFieldFromSetter(property, semanticModel, context.CancellationToken, out var backingField))
{
continue;
}
if (Property.TryFindValue(setter, semanticModel, context.CancellationToken, out var value))
{
if (CanFix(ifStatement, semanticModel, context.CancellationToken, value, backingField) ||
CanFix(ifStatement, semanticModel, context.CancellationToken, value, property))
{
var fieldAccess = backingField.Name.StartsWith("_")
? backingField.Name
: $"this.{backingField.Name}";
var equalsExpression = SyntaxFactory.ParseExpression(
Snippet.EqualityCheck(
property.Type,
"value",
fieldAccess,
semanticModel))
.WithSimplifiedNames();
context.RegisterDocumentEditorFix(
$"Use {equalsExpression}",
(editor, cancellationToken) => editor.ReplaceNode(ifStatement.Condition, equalsExpression),
this.GetType(),
diagnostic);
}
}
}
}