.NET Core CLI 的 F # 入门Get started with F# with the .NET Core CLI

• 08/15/2020
• • c
  • o
  • i

本文介绍如何在 .NET Core CLI (Windows、macOS 或 Linux) 的任何操作系统上开始处理 F #。This article covers how you can get started with F# on any operating system (Windows, macOS, or Linux) with the .NET Core CLI. 其中介绍了如何使用控制台应用程序调用的类库构建多项目解决方案。It goes through building a multi-project solution with a class library that is called by a console application.

先决条件Prerequisites

若要开始，必须安装最新 .NET Core SDK。To begin, you must install the latest .NET Core SDK.

本文假设你知道如何使用命令行并具有首选文本编辑器。This article assumes that you know how to use a command line and have a preferred text editor. 如果尚未使用该选项， Visual Studio Code 是 F # 的文本编辑器。If you don't already use it, Visual Studio Code is a great option as a text editor for F#.

构建简单的多项目解决方案Build a simple multi-project solution

打开命令提示符/终端，并使用 dotnet new 命令创建名为的新解决方案文件 FSNetCore ：Open a command prompt/terminal and use the dotnet new command to create new solution file called FSNetCore:

dotnet new sln -o FSNetCore

运行上述命令后，将生成以下目录结构：The following directory structure is produced after running the previous command:

FSNetCore
    ├── FSNetCore.sln

编写类库Write a class library

将目录更改为 FSNetCore。Change directories to FSNetCore.

使用 dotnet new 命令在名为 library 的 src 文件夹中创建一个类库项目。Use the dotnet new command, create a class library project in the src folder named Library.

dotnet new classlib -lang "F#" -o src/Library

运行上述命令后，将生成以下目录结构：The following directory structure is produced after running the previous command:

└── FSNetCore
    ├── FSNetCore.sln
    └── src
        └── Library
            ├── Library.fs
            └── Library.fsproj

将的内容替换为 Library.fs 以下代码：Replace the contents of Library.fs with the following code:

module Library

open Newtonsoft.Json

let getJsonNetJson value =
    let json = JsonConvert.SerializeObject(value)
    $"I used to be {value} but now I'm {json} thanks to JSON.NET!"

将 NuGet 包上的 Newtonsoft.Js添加到库项目。Add the Newtonsoft.Json NuGet package to the Library project.

dotnet add src/Library/Library.fsproj package Newtonsoft.Json

Library FSNetCore 使用dotnet .sln add命令将项目添加到解决方案：Add the Library project to the FSNetCore solution using the dotnet sln add command:

dotnet sln add src/Library/Library.fsproj

运行 dotnet build 以生成项目。Run dotnet build to build the project. 生成时将还原未解析的依赖项。Unresolved dependencies will be restored when building.

编写使用类库的控制台应用程序Write a console application that consumes the class library

使用 dotnet new 命令在名为 "应用" 的 src 文件夹中创建一个控制台应用程序。Use the dotnet new command, create a console application in the src folder named App.

dotnet new console -lang "F#" -o src/App

运行上述命令后，将生成以下目录结构：The following directory structure is produced after running the previous command:

└── FSNetCore
    ├── FSNetCore.sln
    └── src
        ├── App
        │   ├── App.fsproj
        │   ├── Program.fs
        └── Library
            ├── Library.fs
            └── Library.fsproj

将 Program.fs 文件的内容替换为以下代码：Replace the contents of the Program.fs file with the following code:

open System
open Library

[<EntryPoint>]
let main argv =
    printfn "Nice command-line arguments! Here's what JSON.NET has to say about them:"

    for arg in argv do
        let value = getJsonNetJson arg
        printfn $"{value}"

    0 // return an integer exit code

Library使用dotnet 添加引用添加对项目的引用。Add a reference to the Library project using dotnet add reference.

dotnet add src/App/App.fsproj reference src/Library/Library.fsproj

App使用命令将项目添加到 FSNetCore 解决方案 dotnet sln add ：Add the App project to the FSNetCore solution using the dotnet sln add command:

dotnet sln add src/App/App.fsproj

还原 NuGet 依赖项， dotnet restore 然后运行 dotnet build 以生成项目。Restore the NuGet dependencies, dotnet restore and run dotnet build to build the project.

将目录更改为 src/App 控制台项目，并运行作为参数传递的项目 Hello World ：Change directory to the src/App console project and run the project passing Hello World as arguments:

cd src/App
dotnet run Hello World

应该看到以下结果：You should see the following results:

Nice command-line arguments! Here's what JSON.NET has to say about them:

I used to be Hello but now I'm ""Hello"" thanks to JSON.NET!
I used to be World but now I'm ""World"" thanks to JSON.NET!

后续步骤Next steps

接下来，请查看 F # 教程 ，了解有关不同 F # 功能的详细信息。Next, check out the Tour of F# to learn more about different F# features.