C# 如果未调用基本方法,则visual studio发出警告
我正在研究一种方法,如果我重写基类中的特定方法,但忘记在被重写的基类中调用基类方法,那么VisualStudio会发出警告。例如:C# 如果未调用基本方法,则visual studio发出警告,c#,.net,visual-studio,C#,.net,Visual Studio,我正在研究一种方法,如果我重写基类中的特定方法,但忘记在被重写的基类中调用基类方法,那么VisualStudio会发出警告。例如: class Foo { [SomeAttributeToMarkTheMethodToFireTheWarning] public virtual void A() { ... } } class Bar : Foo { public override void A() { // base.A(); // warning if
class Foo
{
[SomeAttributeToMarkTheMethodToFireTheWarning]
public virtual void A() { ... }
}
class Bar : Foo
{
public override void A()
{
// base.A(); // warning if base.A() is not called
// ...
}
}
到目前为止,我还没有找到一种方法,可能也不可能让编译器直接发出这样的警告。哪怕是第三方工具或使用新的Roslyn.NET编译器平台上的API,你有什么想法可以实现这一点吗
更新:
例如,在AndroidStudio(IntelliJ)中,如果在任何活动中重写
onCreate()
,但忘记调用基本方法super.onCreate()
,则会收到警告。这是我在VS.中需要的行为。如果您想确保某些代码运行,那么您应该更改您的设计:
abstract class Foo
{
protected abstract void PostA();
public void A() {
...
PostA();
}
}
class Bar : Foo
{
protected override void PostA()
{
}
}
//method signature remains the same:
Bar.A();
这样,A()
总是在重写方法之前激发
要具有多个继承性并确保调用了(),还必须将bar设置为抽象:
abstract class Bar : Foo
{
//no need to override now
}
class Baz:Bar
{
protected override void PostA()
{
}
}
在C#中没有办法准确地做你想做的事。这不是VisualStudio的问题。这就是C#的工作原理
可以重写或不重写虚拟方法签名,也可以在基中调用或不调用。您有两个选择虚拟或抽象。您使用的是virtual
,我给了您一个abstract
soltuion。这取决于你选择你想用哪一个
我能想到的最接近你想要的是一个
#警告
。看见但这只会在输出窗口中产生警告,而不会在intellisense中产生警告。基本上。我终于有时间用Roslyn做实验了,看起来我用分析仪找到了解决方案。这是我的解决方案
标记子类中需要重写的方法的属性:
[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public sealed class RequireBaseMethodCallAttribute : Attribute
{
public RequireBaseMethodCallAttribute() { }
}
分析仪:
[DiagnosticAnalyzer(LanguageNames.CSharp)]
public class RequiredBaseMethodCallAnalyzer : DiagnosticAnalyzer
{
public const string DiagnosticId = "RequireBaseMethodCall";
// You can change these strings in the Resources.resx file. If you do not want your analyzer to be localize-able, you can use regular strings for Title and MessageFormat.
// See https://github.com/dotnet/roslyn/blob/master/docs/analyzers/Localizing%20Analyzers.md for more on localization
private static readonly LocalizableString Title = new LocalizableResourceString(nameof(Resources.AnalyzerTitle), Resources.ResourceManager, typeof(Resources));
private static readonly LocalizableString MessageFormat = new LocalizableResourceString(nameof(Resources.AnalyzerMessageFormat), Resources.ResourceManager, typeof(Resources));
private static readonly LocalizableString Description = new LocalizableResourceString(nameof(Resources.AnalyzerDescription), Resources.ResourceManager, typeof(Resources));
private const string Category = "Usage";
private static DiagnosticDescriptor Rule = new DiagnosticDescriptor(DiagnosticId, Title, MessageFormat, Category, DiagnosticSeverity.Warning, isEnabledByDefault: true, description: Description);
public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics { get { return ImmutableArray.Create(Rule); } }
public override void Initialize(AnalysisContext context)
{
context.RegisterCompilationStartAction(AnalyzeMethodForBaseCall);
}
private static void AnalyzeMethodForBaseCall(CompilationStartAnalysisContext compilationStartContext)
{
compilationStartContext.RegisterSyntaxNodeAction(AnalyzeMethodDeclaration, SyntaxKind.MethodDeclaration);
}
private static void AnalyzeMethodDeclaration(SyntaxNodeAnalysisContext context)
{
var mds = context.Node as MethodDeclarationSyntax;
if (mds == null)
{
return;
}
IMethodSymbol symbol = context.SemanticModel.GetDeclaredSymbol(mds) as IMethodSymbol;
if (symbol == null)
{
return;
}
if (!symbol.IsOverride)
{
return;
}
if (symbol.OverriddenMethod == null)
{
return;
}
var overridenMethod = symbol.OverriddenMethod;
var attrs = overridenMethod.GetAttributes();
if (!attrs.Any(ad => ad.AttributeClass.MetadataName.ToUpperInvariant()
== typeof(RequireBaseMethodCallAttribute).Name.ToUpperInvariant()))
{
return;
}
var overridenMethodName = overridenMethod.Name.ToString();
string methodName = overridenMethodName;
var invocations = mds.DescendantNodes().OfType<MemberAccessExpressionSyntax>().ToList();
foreach (var inv in invocations)
{
var expr = inv.Expression;
if ((SyntaxKind)expr.RawKind == SyntaxKind.BaseExpression)
{
var memberAccessExpr = expr.Parent as MemberAccessExpressionSyntax;
if (memberAccessExpr == null)
{
continue;
}
// compare exprSymbol and overridenMethod
var exprMethodName = memberAccessExpr.Name.ToString();
if (exprMethodName != overridenMethodName)
{
continue;
}
var invokationExpr = memberAccessExpr.Parent as InvocationExpressionSyntax;
if (invokationExpr == null)
{
continue;
}
var exprMethodArgs = invokationExpr.ArgumentList.Arguments.ToList();
var ovrMethodParams = overridenMethod.Parameters.ToList();
if (exprMethodArgs.Count != ovrMethodParams.Count)
{
continue;
}
var paramMismatch = false;
for (int i = 0; i < exprMethodArgs.Count; i++)
{
var arg = exprMethodArgs[i];
var argType = context.SemanticModel.GetTypeInfo(arg.Expression);
var param = arg.NameColon != null ?
ovrMethodParams.FirstOrDefault(p => p.Name.ToString() == arg.NameColon.Name.ToString()) :
ovrMethodParams[i];
if (param == null || argType.Type != param.Type)
{
paramMismatch = true;
break;
}
exprMethodArgs.Remove(arg);
ovrMethodParams.Remove(param);
i--;
}
// If there are any parameters left without default value
// then it is not the base method overload we are looking for
if (ovrMethodParams.Any(p => p.HasExplicitDefaultValue))
{
continue;
}
if (!paramMismatch)
{
// If the actual arguments match with the method params
// then the base method invokation was found
// and there is no need to continue the search
return;
}
}
}
var diag = Diagnostic.Create(Rule, mds.GetLocation(), methodName);
context.ReportDiagnostic(diag);
}
}
[DiagnosticanAnalyzer(LanguageNames.CSharp)]
公共类RequiredBaseMethodCallAnalyzer:DiagnosticanAnalyzer
{
public const string DiagnosticId=“requirebemethodcall”;
//您可以在Resources.resx文件中更改这些字符串。如果您不希望您的分析器能够本地化,可以使用常规字符串作为标题和消息格式。
//看https://github.com/dotnet/roslyn/blob/master/docs/analyzers/Localizing%20Analyzers.md 有关本地化的更多信息
private static readonly LocalizableString Title=新的LocalizableResourceString(nameof(Resources.AnalyzerTitle)、Resources.ResourceManager、typeof(Resources));
private static readonly LocalizableString MessageFormat=新的LocalizableResourceString(nameof(Resources.AnalyzerMessageFormat)、Resources.ResourceManager、typeof(Resources));
private static readonly LocalizableString Description=新的LocalizableResourceString(nameof(Resources.AnalyzerDescription)、Resources.ResourceManager、typeof(Resources));
private const string Category=“用法”;
私有静态DiagnosticDescriptor规则=新的DiagnosticDescriptor(DiagnosticId、标题、消息格式、类别、DiagnosticSeverity.Warning、IsEnabled默认为true,描述为description);
公共覆盖ImmutableArray支持的诊断{get{return ImmutableArray.Create(Rule);}
公共覆盖无效初始化(AnalysisContext上下文)
{
RegisterCompilationStartAction(AnalyzeMethodForBaseCall);
}
专用静态无效分析方法BaseCall(编译StartAnalysisContext编译StartContext)
{
编译StartContext.RegisterSyntaxNodeAction(AnalyzeMethodDeclaration,SyntaxKind.MethodDeclaration);
}
私有静态void分析方法声明(SyntaxNodeAnalysisContext上下文)
{
var mds=context.Node as MethodDeclarationSyntax;
如果(mds==null)
{
返回;
}
IMethodSymbol symbol=context.SemanticModel.GetDeclaredSymbol(mds)作为IMethodSymbol;
如果(符号==null)
{
返回;
}
如果(!symbol.IsOverride)
{
返回;
}
if(symbol.overridedenMethod==null)
{
返回;
}
var OverrideMethod=symbol.OverrideMethod;
var attrs=overrideMethod.GetAttributes();
如果(!attrs.Any(ad=>ad.AttributeClass.MetadataName.ToUpperInvariant())
==typeof(RequireBeamMethodCallAttribute).Name.ToUpperInvariant())
{
返回;
}
var OverrideMethodName=OverrideMethod.Name.ToString();
string methodName=重写的methodName;
var invocations=mds.degenantnodes().OfType().ToList();
foreach(调用中的var inv)
{
变量表达式=变量表达式;
if((SyntaxKind)expr.RawKind==SyntaxKind.BaseExpression)
{
var memberAccessExpr=expr.Parent作为MemberAccessExpressionSyntax;
if(memberAccessExpr==null)
{
继续;
}
//比较exprSymbol和OverrideMethod
var exprMethodName=memberAccessExpr.Name.ToString();
if(exprMethodName!=重写方法名)
{
继续;
}
var invokationExpr=memberAccessExpr.Parent作为InvokationExpressionSyntax;
if(invokationExpr==null)
{
继续;
}
var exprMethodArgs=invokationExpr.ArgumentList.Arguments.ToList();
var ovrMethodParams=OverrideMethod.Parameters.ToList();
if(exprMethodArgs.Count!=ovrMethodParams.Count)
{
继续;
}
var参数不匹配=假;
for(int i=0;i[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(BaseMethodCallCodeFixProvider)), Shared]
public class BaseMethodCallCodeFixProvider : CodeFixProvider
{
private const string title = "Add base method invocation";
public sealed override ImmutableArray<string> FixableDiagnosticIds
{
get { return ImmutableArray.Create(RequiredBaseMethodCallAnalyzer.DiagnosticId); }
}
public sealed override FixAllProvider GetFixAllProvider()
{
// See https://github.com/dotnet/roslyn/blob/master/docs/analyzers/FixAllProvider.md for more information on Fix All Providers
return WellKnownFixAllProviders.BatchFixer;
}
public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
var diagnostic = context.Diagnostics.First();
var diagnosticSpan = diagnostic.Location.SourceSpan;
// Register a code action that will invoke the fix.
context.RegisterCodeFix(
CodeAction.Create(
title: title,
createChangedDocument: c => AddBaseMethodCallAsync(context.Document, diagnosticSpan, c),
equivalenceKey: title),
diagnostic);
}
private async Task<Document> AddBaseMethodCallAsync(Document document, TextSpan diagnosticSpan, CancellationToken cancellationToken)
{
var root = await document.GetSyntaxRootAsync(cancellationToken);
var node = root.FindNode(diagnosticSpan) as MethodDeclarationSyntax;
var args = new List<ArgumentSyntax>();
foreach (var param in node.ParameterList.Parameters)
{
args.Add(SyntaxFactory.Argument(SyntaxFactory.ParseExpression(param.Identifier.ValueText)));
}
var argsList = SyntaxFactory.SeparatedList(args);
var exprStatement = SyntaxFactory.ExpressionStatement(
SyntaxFactory.InvocationExpression(
SyntaxFactory.MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
SyntaxFactory.BaseExpression(),
SyntaxFactory.Token(SyntaxKind.DotToken),
SyntaxFactory.IdentifierName(node.Identifier.ToString())
),
SyntaxFactory.ArgumentList(argsList)
),
SyntaxFactory.Token(SyntaxKind.SemicolonToken)
);
var newBodyStatements = SyntaxFactory.Block(node.Body.Statements.Insert(0, exprStatement));
var newRoot = root.ReplaceNode(node.Body, newBodyStatements).WithAdditionalAnnotations(Simplifier.Annotation);
return document.WithSyntaxRoot(newRoot);
}
}
/// <summary>
/// Base class for making sure that descendants always invoke overridable
/// methods of base.
/// </summary>
public abstract class Overridable
{
private sealed class InvocationGuard : IDisposable
{
private readonly Overridable overridable;
public readonly string MethodName;
public bool Invoked;
public InvocationGuard( Overridable overridable, string methodName )
{
this.overridable = overridable;
MethodName = methodName;
}
public void Dispose()
{
Assert( ReferenceEquals( overridable.invocationStack.Peek(), this ) );
Assert( Invoked );
overridable.invocationStack.Pop();
}
}
private readonly Stack<InvocationGuard> invocationStack = new Stack<InvocationGuard>();
public IDisposable NewOverridableGuard( string methodName )
{
Assert( ReflectionHelpers.MethodExistsAssertion( GetType(), methodName ) );
var invocationGuard = new InvocationGuard( this, methodName );
invocationStack.Push( invocationGuard );
return invocationGuard;
}
public void OverridableWasInvoked( [CanBeNull][CallerMemberName] string methodName = null )
{
Assert( methodName != null );
Assert( ReflectionHelpers.MethodExistsAssertion( GetType(), methodName ) );
InvocationGuard invocationGuard = invocationStack.Peek();
Assert( invocationGuard.MethodName == methodName );
Assert( !invocationGuard.Invoked );
invocationGuard.Invoked = true;
}
}
protected internal void RaisePropertyChanged( [CallerMemberName] string propertyName = null )
{
using( NewOverridableGuard( nameof(OnPropertyChanged) ) ) //Add this to your existing code
OnPropertyChanged( propertyName );
}
protected virtual void OnPropertyChanged( string propertyName )
{
OverridableWasInvoked(); //Add this to your existing code
PropertyChanged?.Invoke( this, new PropertyChangedEventArgs( propertyName ) );
}