为了充分理解和利用提供了新的.NET Framework 4.0的到来，新功能和增强功能的优势，我想获得的真实世界的的一个示例应用程序的< A HREF =htt​​p://msdn.microsoft.com/en-us/library/system.diagnostics.contracts.aspx> code合同的。

In order to fully understand and take advantage of the new features and enhancements provided with the coming of the new .NET Framework 4.0, I would like to get an example of real-world application of Code Contracts.

我想获得一个code样品用简短的解释帮我拿起来与它运行。

I would like to get a code sample with a brief explanation to help me get up and running with it.

推荐答案

从The code合约用户手册：

合约让你的前preSS preconditions，后置条件和对象不变量在code运行时   检查，静态分析和文档。

Contracts allow you to express preconditions, postconditions and object invariants in your code for runtime checking, static analysis, and documentation.

code合同用于静态验证;想象一下，如果 - 在编译的时候 - 你抓到不仅语法错误，但也的的逻辑错误。这是静态的程序验证的愿景。

Code Contracts are used for static verification; imagine if - at compile time - you caught not only syntax errors but also logic errors. This is the vision of static program verification.

您可以使用合同（和静态验证），以减少测试成本......特别是回归测试。举个例子，假设我写一些code这满足了一些商务需求......但后来，性能需求的变化，而我需要优化。如果我先写一份合同，然后 - 当我的新的优化code被证实 - 如果它不再履行原合同，我会得到一个错误信息在我的IDE，就像如果我有一个编译时错误。这样一来，你会发现并解决的bug几乎立即，其成本远低于一轮测试。

You could use contracts (and static verification) to reduce the cost of testing... in particular regression testing. As an example, let's say I write some code which fulfills some business needs... but later, performance needs change, and I'm required to optimize. If I first write a contract, then - when my new optimized code is verified - if it no longer fulfills the original contract I'll get an error message in my IDE, just like if I had a compile time error. As a result, you find and resolve the bug almost immediately, which costs less than a round of testing.