使用Roslyn时如何在方法中验证参数的类型 [英] How to validate a parameter's type in method when using Roslyn

问题描述

我正在与Roslyn进行代码分析，以验证即使我具有以下签名

  public void MyMethod （对象anObject，MyCustomObject customObject）； 
  

我只想从MyCustomObject接收一个字符串（第一个）和一个孩子作为参数（第二个）。我对签名无能为力，不能更改。

这是我评估方法的内容（以下是代码段）

  public void OnMethodInvocation（SyntaxNodeAnalysisContext context）
 {
 var invocation = context.Node作为InvocationExpressionSyntax; 
 var symbol = context.SemanticModel.GetSymbolInfo（invocation）.Symbol as IMethodSymbol; 
 
 if（symbol？.Name.ToString（）== MyMethod）
 {
 var parameterList = invocation.Parameters; 
} 
  

到目前为止，我可以通过属性Parameters（符号）来操作IParameterSymbol对象。参数）。我没有得到以下内容：我已经遍历了包含两个参数的IEnumerable结果，但是由于方法签名，它希望接收一个对象和一个MyCustomObject实例。我目前无法确定第一个参数确实是对象而不是字符串（仅是示例，可能是其他任何东西），并且当我期望MyCustomObject的孩子时，如果我给它一个null，我想知道它是一个null参数。

我将感谢任何能够将我从这种棘手的情况中解脱出来的人！ / p>

更新

当我进入时，这是给我什么样的信息ArgumentSyntax对象：

  ArgumentSyntax参数异常
 ContainsAnnotations：否
 ContainsDiagnostics：否
 ContainsDirectives ：false 
 ContainsSkippedText：false 
表达式：IdentifierNameSyntax IdentifierName异常
 FullSpan：{[550..559）} 
 HasLeadingTrivia：错误
 HasStructuredTrivia：错误
 HasTrailingTrivia：假
 IsMissing：假
 IsStructuredTrivia：假
 KindText： Argument 
语言： C＃ 
 NameColon：空
父级（Microsoft.CodeAnalysis.SyntaxNode）：ArgumentListSyntax ArgumentList（异常，异常）
 ParentTrivia：SyntaxTrivia None 
 RawKind：8638 
 RefOrOutKeyword：语法令牌无
跨度：{[550..559）} 
 SpanStart：550 
  

解决方案

您应该做的是获取参数（不是参数-它们是不同的东西！）并调用 SeguticModel.GetTypeInfo（）上的ArgumentSyntax。这将为您提供要传递的表达式的类型。从那里您可以进行所需的任何检查。

I'm doing code analysis with Roslyn in order to validate that even though I have the following signature

public void MyMethod(object anObject, MyCustomObject customObject);

I only want to receive, as parameters, a string (1st) and a child from MyCustomObject (2nd). I have no power over the signature, it cannot be changed.

Here's what I did to evaluate my method (Here's a snippet)

    public void OnMethodInvocation(SyntaxNodeAnalysisContext context)
    {
        var invocation= context.Node as InvocationExpressionSyntax;
        var symbol = context.SemanticModel.GetSymbolInfo(invocation).Symbol as IMethodSymbol;

        if (symbol?.Name.ToString()== "MyMethod")
        {
            var parameterList = invocation.Parameters;
        }

As of now, I can manipulate my IParameterSymbol objects from the property Parameters (symbol.Parameters). What I don't get is the following : I've gone through my result IEnumerable containing both my parameters, but because of the method signature, it expects to receive an object and a MyCustomObject instances. I'm not in a position (at the moment) to be certain that the first parameter is indeed an object and not a string (merely an example, could have been anything else) and that when I'm expecting a child of MyCustomObject, if I give it a null, I want to know it's a null parameter.

I'll be grateful to anyone who can un-stuck me from this sticky situation !

UPDATES

Here's what kind of information is given to me when I get into an ArgumentSyntax object :

ArgumentSyntax Argument exception
    ContainsAnnotations: false
    ContainsDiagnostics: false
    ContainsDirectives: false
    ContainsSkippedText: false
    Expression: IdentifierNameSyntax IdentifierName exception
    FullSpan: {[550..559)}
    HasLeadingTrivia: false
    HasStructuredTrivia: false
    HasTrailingTrivia: false
    IsMissing: false
    IsStructuredTrivia: false
    KindText: "Argument"
    Language: "C#"
    NameColon: null
    Parent (Microsoft.CodeAnalysis.SyntaxNode): ArgumentListSyntax ArgumentList (exception,exception)
    ParentTrivia: SyntaxTrivia None 
    RawKind: 8638
    RefOrOutKeyword: SyntaxToken None 
    Span: {[550..559)}
    SpanStart: 550

解决方案

What you should be doing is getting the arguments (not parameters -- they are different things!) and calling SemanticModel.GetTypeInfo() on the ArgumentSyntax. That'll give you the type of the expression being passed. From there you can do whatever checks you need.

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