如何从VS2010立即窗口调用F＃函数 [英] How do I invoke an F# function from the VS2010 immediate window

问题描述

在调试F＃应用程序时，我希望能够从VS2010立即窗口调用F＃方法，但似乎不起作用。问题似乎是F＃方法实际上是FSharpFunc对象。我尝试使用Invoke方法，但交互式窗口无法识别它。

解决方案

Visual Studio的F＃集成不在立即窗口（或手表）中不支持F＃表达式，所以唯一的选择是编写与F＃使用的编译表示相对应的C＃代码。我尝试这样做，我有与您所描述的相同的问题 - Invoke 方法似乎在（Reflector）中，但Visual Studio不想调用它直接我尝试使用以下示例：

  let foo f = 
 let n = f 1 2 // Breakpoint here 
n + 1 
  

然而，还有其他方法可以调用该函数。在这种情况下，F＃编译器生成的实际代码是调用 InvokeFast 方法。如果您在直接窗口中输入以下内容，它将起作用：

  Microsoft.FSharp.Core.FSharpFunc< int，int> ;. InvokeFast< int>（f，1,2）| 
  

也可以调用通常的 Invoke dynamic （证明该方法实际上在那里！）：

 （（动态）f）.Invoke（1，2）
  

仅当您添加对 Microsoft.CSharp.dll 的引用（并使用某些在程序集中定义的类型，例如作为注释，以便它被加载）。

While debugging an F# application, I would like to be able to invoke an F# method from the VS2010 immediate window but it doesn't seem to work. The problem appears to be that F# methods are actually FSharpFunc objects. I tried using the "Invoke" method but the interactive window doesn't recognize it.

解决方案

The F# integration for Visual Studio doesn't support F# expressions in immediate window (or watches), so the only option is to write C# code corresponding to the compiled representation that F# uses. I tried doing that and I'm having the same issue as you described - the Invoke method appears to be there (in Reflector), but Visual Studio doesn't want to call it directly. I tried it using the following example:

let foo f = 
  let n = f 1 2 // Breakpoint here
  n + 1

However, there are other ways to call the function. In this case, the actual code generated by the F# compiler is a call to InvokeFast method. If you type the following to the immediate window, it works:

Microsoft.FSharp.Core.FSharpFunc<int, int>.InvokeFast<int>(f, 1, 2)  |

It also appears that you can call the usual Invoke method using dynamic from C# 4.0 (proving that the method is actually there!):

((dynamic)f).Invoke(1, 2)

This works only if you add reference to Microsoft.CSharp.dll (and use some type defined in the assembly somewhere in your code - e.g. as an annotation - so that it gets loaded).

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