问题描述
这是我的代码:
public class RegularPolygon
{
public int VertexCount;
public double SideLength;
public RegularPolygon(int vertexCount, double sideLength)
{
Contract.Requires(vertexCount >= 3);
VertexCount = vertexCount;
SideLength = sideLength;
}
[ContractInvariantMethod]
private void RegularPolygonInvariants()
{
Contract.Invariant(VertexCount>=3);
}
}
我都尝试过 Contract.Requires 和 Contract.Invariant 方法,可防止vertexCount变量小于或等于2;但是,我仍然可以初始化2面或更少面的RegularPolygon。我的(简化的)NUnit测试如下所示:
I have tried with both the Contract.Requires and Contract.Invariant methods to prevent the vertexCount variable from becoming less than or equal to 2; however I am still able to initialise a RegularPolygon with 2 or fewer sides. My (simplified) NUnit test looks like this:
[TestFixture]
class TestRegularPolygon
{
private RegularPolygon _polygon;
[SetUp]
public void Init()
{
_polygon = new RegularPolygon(1, 50);
}
[Test]
public void Constructor()
{
Assert.That(_polygon.VertexCount,Is.GreaterThanOrEqualTo(3));
}
}
上述测试也通过了无法弄清楚原因!
The above test also passes and I cannot figure out why!
起初,我认为ReSharper可能已经搞砸了,因为它使行变灰并在我尝试在其中使用方法时显示此消息。 合同
命名空间:
At first I thought ReSharper might have been messing something up because it greys out the line and displays this message whenever I try to use a method in the Contract
namespace:
但是,挂起R#并运行该程序时,编译器不会生成方法调用,因为该方法是有条件的,或者它是不执行的部分方法。 NUnit中的测试具有相同的结果,而VS中没有错误或警告。因此,我认为这仅仅是因为ReSharper尚未突出强调代码合同的兼容性。
But suspending R# and running the tests in NUnit has the same result with no errors or warnings in VS either. So I assume that is just because ReSharper does not have highlighting compatibility for code contracts yet.
我看了看文档,据我所知我不应该这样做
I have looked at the documentation and as far as I can tell I shouldn't be having this problem.
我是错误地使用了代码合同,还是我的环境阻止了它以某种方式工作?
谢谢。
推荐答案
要检查的第一件事-您是否已打开合同检查功能?如果没有,您的任何合同都不会做任何事情。那也将解释R#警告。在构建属性的代码合同下查看,并在运行时检查下查看其内容。
First thing to check - have you actually got contract checking turned on? If not, none of your contracts will do anything. That would explain the R# warning, too. Look under "Code Contracts" in the build properties, and see what it says under "Runtime Checking".
根据注释,确保您有 CONTRACTS_FULL
定义为编译符号-似乎是R#所需要的。
As per comments, ensure you have CONTRACTS_FULL
defined as a compilation symbol - that appears to be what R# requires.
第二点:您有公共可变字段,该字段是表示有人在任何时候都会侵犯您的不变式
Second point: you've got public mutable fields, which means your invariant can be violated at any moment by someone writing
polygon.VertexCount = 0;
请不要使用公共字段,尤其是不可写的字段。 :)
Please don't use public fields, particularly not writable ones. :)
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