public sealed override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
{
var root = await context.Document
.GetSyntaxRootAsync(context.CancellationToken)
.ConfigureAwait(false);
var node = root.FindNode(context.Span);
var parameter = node.Parent as ParameterSyntax;
if (parameter == null)
{
return;
}
var parameterName = RoslynHelpers.GetParameterName(parameter);
var underscorePrefix = $"_{parameterName}";
var uppercase = $"{parameterName.Substring(0, 1).ToUpper()}{parameterName.Substring(1)}";
if (RoslynHelpers.VariableExists(root, parameterName, underscorePrefix, uppercase))
{
return;
}
var action = CodeAction.Create(
$"Introduce as private field '{underscorePrefix}'",
ct =>
CreateFieldAsync(context, parameter, parameterName, underscorePrefix, ct));
context.RegisterRefactoring(action);
}
private async Task <Document> CreateFieldAsync(
CodeRefactoringContext context,
ParameterSyntax parameter,
string paramName, string fieldName,
CancellationToken cancellationToken)
{
var oldConstructor = parameter
.Ancestors()
.OfType <ConstructorBlockSyntax>()
.First();
ExpressionSyntax expression = CreateAssignmentExpression(paramName);
var constructorBody = SyntaxFactory.AssignmentStatement(
SyntaxKind.SimpleAssignmentStatement,
SyntaxFactory.IdentifierName(fieldName),
SyntaxFactory.Token(SyntaxKind.EqualsToken),
expression);
var newConstructor = oldConstructor.AddStatements(constructorBody);
var oldClass = parameter.FirstAncestorOrSelf <ClassBlockSyntax>();
var oldClassWithNewCtor = oldClass.ReplaceNode(oldConstructor, newConstructor);
var fieldDeclaration = CreateFieldDeclaration(RoslynHelpers.GetParameterType(parameter), fieldName);
fieldDeclaration = fieldDeclaration.WithTrailingTrivia(SyntaxFactory.CarriageReturnLineFeed);
var members = oldClassWithNewCtor.Members.Insert(0, fieldDeclaration);
var newClass = oldClassWithNewCtor
.WithMembers(members)
.WithAdditionalAnnotations(Formatter.Annotation);
var oldRoot = await context.Document
.GetSyntaxRootAsync(cancellationToken)
.ConfigureAwait(false);
var newRoot = oldRoot.ReplaceNode(oldClass, newClass);
return(context.Document.WithSyntaxRoot(newRoot));
}
private async Task <Document> CreateFieldAsync(
CodeRefactoringContext context,
ParameterSyntax parameter,
string paramName, string fieldName,
CancellationToken cancellationToken,
bool isReferenceType)
{
var oldConstructor = parameter
.Ancestors()
.OfType <ConstructorDeclarationSyntax>()
.First();
ExpressionSyntax expression = CreateAssignmentExpression(paramName, isReferenceType);
var newConstructor =
oldConstructor
.WithBody(
oldConstructor.Body.AddStatements(
SyntaxFactory.ExpressionStatement(
SyntaxFactory.AssignmentExpression(
SyntaxKind.SimpleAssignmentExpression,
SyntaxFactory.IdentifierName(fieldName),
expression))));
var oldClass = parameter.FirstAncestorOrSelf <ClassDeclarationSyntax>();
var oldClassWithNewCtor = oldClass.ReplaceNode(oldConstructor, newConstructor);
var fieldDeclaration = RoslynHelpers.CreateFieldDeclaration(RoslynHelpers.GetParameterType(parameter), fieldName);
var newClass = oldClassWithNewCtor
.WithMembers(oldClassWithNewCtor.Members.Insert(0, fieldDeclaration))
.WithAdditionalAnnotations(Formatter.Annotation);
var oldRoot = await context.Document
.GetSyntaxRootAsync(cancellationToken)
.ConfigureAwait(false);
var newRoot = oldRoot.ReplaceNode(oldClass, newClass);
return(context.Document.WithSyntaxRoot(newRoot));
}