如何测试一个方法参数装饰有一个属性？ [英] How to test that a method argument is decorated with an attribute?

问题描述

这可能是重复的，但我无法找到我要找的问题，所以我要求它。

This is probably a duplicate, but I can't find the question I'm looking for, so I'm asking it.

你怎么测试方法的参数装饰着attribte？例如，下面的MVC的操作方法，使用FluentValidation的 CustomizeValidatorAttribute ：

How do you test that a method argument is decorated with an attribte? For example, the following MVC action method, using FluentValidation's CustomizeValidatorAttribute:

[HttpPost]
[OutputCache(VaryByParam = "*", Duration = 1800)]
public virtual ActionResult ValidateSomeField(
    [CustomizeValidator(Properties = "SomeField")] MyViewModel model)
{
    // code
}

我敢肯定，我将不得不使用反射，希望与强类型的lambda表达式。但不知道从哪里开始。

I'm sure I'll have to use reflection, hopefully with strongly-typed lambdas. But not sure where to start.

推荐答案

一旦你得到通过思考a GetMethodInfo 调用该方法的手柄，你可以简单地调用 GetParameters（）上的方法，然后对每个参数，您可以检查 GetCustomAttributes（）呼吁类型的实例十，例如：

Once you get a handle on the method with a GetMethodInfo call via Reflection, you can simply call GetParameters() on that method, and then for each parameter, you can inspect the GetCustomAttributes() call for instances of type X. For example:

Expression<Func<MyController, ActionResult>> methodExpression = 
    m => m.ValidateSomeField(null);
MethodCallExpression methodCall = (MethodCallExpression)methodExpression.Body;
MethodInfo methodInfo = methodCall.Method;

var doesTheMethodContainAttribute = methodInfo.GetParameters()
      .Any(p => p.GetCustomAttributes(false)
           .Any(a => a is CustomizeValidatorAttribute)));

Assert.IsTrue(doesTheMethodContainAttribute);

本试验，例如，如果将任何参数包含的属性告诉你。如果你想要一个特定参数，您将需要修改 GetParameters 呼吁为更具体的东西。

This test, for example, would tell you if ANY of the parameters contained the attribute. If you wanted a specific parameter, you would need to change the GetParameters call into something more specific.

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