如何在运行时检测丢失的 .NET 引用? [英] How to detect a missing .NET reference at runtime?

问题描述

我的应用程序包含对外部库(SQL Server 管理对象)的引用.显然，如果运行时系统上不存在该库，只要没有调用使用该库中的类的方法，应用程序仍然可以运行.

My application contains references to an external library (the SQL Server Management Objects). Apparently, if the library is not present on the run-time system, the application still works as long as no methods are called that use classes from this library.

问题 1:这是指定的行为还是 CLR 加载库方式的(幸运的)副作用?

为了检测引用是否可访问，我目前使用这样的代码:

To detect whether the reference is accessible, I currently use code like this:

Function IsLibraryAvailable() As Boolean
    Try
        TestMethod()
    Catch ex As FileNotFoundException
        Return False
    End Try
    Return True
End Function

Sub TestMethod()
    Dim srv As New Smo.Server()  ' Try to create an object in the library
End Sub

它有效，但它似乎很丑陋.请注意，只有当 TestMethod 是一个单独的方法时才有效，否则将在 IsLibraryAvailable 的 beginning 抛出异常(在 try-catch 之前，即使对象实例化发生在 try-catch 块中).

It works, but it seems to be quite ugly. Note that it only works if TestMethod is a separate method, otherwise the exception will be thrown at the beginning of IsLibraryAvailable (before the try-catch, even if the object instantiation occurrs within the try-catch block).

问题 2:有更好的选择吗?

特别是，我担心函数内联等优化可能会阻止我的代码工作.

In particular, I'm afraid that optimizations like function inlining could stop my code from working.

推荐答案

这是意料之中的，因为 JIT 在每个方法级别是惰性的.请注意，内联在这里不是问题，因为这也是 JIT 问题，而不是编译器问题.

That is expected, since the JIT is lazy at the per-method level. Note that inlining isn't an issue here, since that is also a JIT concern, not a compiler concern.

更好的选择:

• 确保应用已安装所需的一切
• 使用 ilmerge 或类似工具创建单个程序集(如果可能)

就我个人而言，我只会使用第一个选项.

Personally, I'd just use the first option.

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