[英]C# How can i detect EvenHandler subscription in Roslyn
I'm writing a custom analyzer rule using Roslyn. 我正在使用Roslyn编写自定义分析器规则。
I want to find a method which is a handler for some event (via subscription). 我想找到一个方法来处理某些事件(通过订阅)。 Like this: 像这样:
public class Counter
{
public event EventHandler ThresholdReached;
}
public class TestEvent
{
public TestEvent()
{
Counter с = new Counter();
с.ThresholdReached += OnThresholdReached;
}
private void OnThresholdReached(object sender, EventArgs e)
{
}
}
In my realization it looks: 在我的认识中,它看起来是:
private static void HandleMethodDeclaration(SyntaxNodeAnalysisContext context)
{
MethodDeclarationSyntax methodDeclaration = (MethodDeclarationSyntax)context.Node;
if (methodDeclaration.Identifier.IsMissing)
{
return;
}
IMethodSymbol methodSymbol = context.SemanticModel.GetDeclaredSymbol(methodDeclaration);
}
I don't know how to detect that OnThresholdReached is subscription of Event ThresholdReached . 我不知道如何检测OnThresholdReached是Event ThresholdReached的订阅。 If someone knows how to do it, please help=) 如果有人知道该怎么做,请帮助=)
In an analyzer, you cannot know only from looking at a MethodDeclarationSyntax
, whether that method is converted to a delegate or not. 在分析器中,仅通过查看MethodDeclarationSyntax
不能知道该方法是否转换为委托。 Because of that, you can not know (only from looking at a MethodDeclarationSyntax
) whether that delegate is passed to the add accessor of an event or not. 因此,您不能(仅通过查看MethodDeclarationSyntax
)不知道该委托是否传递给事件的添加访问器。
First of all, remember that a Roslyn analyzer can only see usages in the current assembly (project). 首先,请记住Roslyn分析器只能查看当前程序集(项目)中的用法。 If your method is converted to a delegate in another assembly, there is no way for the analyzer to see this. 如果将您的方法转换为另一个程序集中的委托,则分析器将无法看到此结果。
Secondly, remember that 其次,请记住
с.ThresholdReached += OnThresholdReached;
may be expressed as 可以表示为
EventHandler handler = OnThresholdReached;
с.ThresholdReached += handler;
If you only want to detect the first case, you can look at AssignmentExpressionSyntax
instances of kind SyntaxKind.AddAssignmentExpression
, and analyze those. 如果只想检测第一种情况,则可以查看SyntaxKind.AddAssignmentExpression
类型的AssignmentExpressionSyntax
实例,并进行分析。
If you want to detect all cases where a method group is converted to a delegate, you need to look at all instances of type SimpleNameSyntax
and analyze those as follows: 如果要检测将方法组转换为委托的所有情况,则需要查看所有类型为SimpleNameSyntax
实例,并进行如下分析:
void Analyze(SyntaxNodeAnalysisContext context)
{
var node = context.Node as SimpleNameSyntax;
// we're only interested in delegates
var type = context.SemanticModel.GetTypeInfo(node, context.CancellationToken).ConvertedType;
if (type == null || type.TypeKind != TypeKind.Delegate)
{
return;
}
// we're only interested in methods from the current assembly
var symbol = context.SemanticModel.GetSymbolInfo(node, context.CancellationToken).Symbol;
if (symbol == null ||
symbol.Kind != SymbolKind.Method ||
!symbol.ContainingAssembly.Equals(context.SemanticModel.Compilation.Assembly))
{
return;
}
// now you know symbol is a method in the same assembly, that is converted to a delegate
}
To find the source code for that method, see https://stackoverflow.com/a/45362532/1403794 . 要查找该方法的源代码,请参阅https://stackoverflow.com/a/45362532/1403794 。
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