.NET 10 File-Based Apps：一个 .cs 文件搞定一切，C# 终于也能像 Python 一样写脚本了！

dotnet --version
# 输出应为 10.0 或更高

Console.WriteLine("Hello, File-Based App!");

dotnet run hello.cs

dotnet hello.cs

#:package Microsoft.Data.SQLite@8.0.0

using Microsoft.Data.Sqlite;

var connectionString = "Data Source=:memory:";
using var connection = new SqliteConnection(connectionString);
connection.Open();

var command = connection.CreateCommand();
command.CommandText = "CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT);" +
                      "INSERT INTO users (name) VALUES ('山友');" +
                      "SELECT * FROM users;";

using var reader = command.ExecuteReader();
while (reader.Read())
{
    Console.WriteLine($"ID: {reader.GetInt32(0)}, Name: {reader.GetString(1)}");
}

dotnet run sqlite-demo.cs

ID: 1, Name: 山友

#:sdk Microsoft.NET.Sdk.Web
#:package Swashbuckle.AspNetCore

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/", () => "Hello from File-Based Web App!");
app.MapGet("/api/health", () => new { status = "ok", timestamp = DateTime.UtcNow });

app.Run();

dotnet run webapi.cs

#:property TargetFramework=net10.0
#:property PublishAot=false
#:property LogLevel=$([MSBuild]::ValueOrDefault('$(LOG_LEVEL)', 'Information'))

Console.WriteLine($"Current Log Level: {Environment.GetEnvironmentVariable("LOG_LEVEL") ?? "Information"}");

#:project ../SharedLibrary/SharedLibrary.csproj

using SharedLibrary;

Console.WriteLine(Helper.GetMessage());

# 标准方式
dotnet run --file app.cs

# 简写（推荐）
dotnet run app.cs

# 更简写（当目录无 .csproj 时）
dotnet app.cs

# 传递参数
dotnet run app.cs -- arg1 arg2

# 从标准输入管道执行
echo 'Console.WriteLine("hello from stdin!");' | dotnet run -

# 编译
dotnet build app.cs

# 清理构建产物
dotnet clean app.cs

# 清理所有 file-based apps 缓存
dotnet clean file-based-apps

# 发布（默认启用 Native AOT，生成独立可执行文件）
dotnet publish app.cs

# 打包为 .NET 全局工具
dotnet pack app.cs

# 转换为传统项目（平滑升级路径）
dotnet project convert app.cs

# 显式恢复 NuGet 包
dotnet restore app.cs

# 构建时自动恢复（默认行为）
dotnet build app.cs

#:property PublishAot=false

# 设置机密
dotnet user-secrets set "ApiKey" "your-secret-value" --file app.cs

# 查看机密
dotnet user-secrets list --file app.cs

#!/usr/bin/env dotnet
#:package Spectre.Console

using Spectre.Console;

AnsiConsole.MarkupLine("[green]Hello, World![/]");

chmod +x app.cs
./app.cs

// app.run.json
{
  "profiles": {
    "http": {
      "commandName": "Project",
      "launchBrowser": true,
      "applicationUrl": "http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "https": {
      "commandName": "Project",
      "launchBrowser": true,
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

dotnet run app.cs --launch-profile https

📁 MyProject/
├── MyProject.csproj
├── Program.cs
└──📁 scripts/
    └── utility.cs  // 会受到 MyProject.csproj 的隐式文件影响

📁 MyProject/
├── MyProject.csproj
└── Program.cs
📁 scripts/
└── utility.cs  // 独立目录，避免干扰

#:package Newtonsoft.Json

using Newtonsoft.Json;

var data = new { Name = "File-Based App", Version = "1.0", Features = new[] { "Fast", "Simple", "Powerful" } };
Console.WriteLine(JsonConvert.SerializeObject(data, Formatting.Indented));

#!/usr/bin/env dotnet
#:package Spectre.Console
#:package System.CommandLine

using Spectre.Console;
using System.CommandLine;

// 构建一个功能完整的 CLI 工具
var rootCommand = new RootCommand("文件批量重命名工具");
var patternOption = new Option<string>("--pattern", "匹配模式");
rootCommand.AddOption(patternOption);

rootCommand.SetHandler((string pattern) =>
{
    AnsiConsole.MarkupLine($"[blue]正在处理匹配模式: {pattern}[/]");
    // 业务逻辑...
}, patternOption);

await rootCommand.InvokeAsync(args);

#:package Dapper
#:package Microsoft.Data.SqlClient
#:package CsvHelper

using Dapper;
using Microsoft.Data.SqlClient;
using CsvHelper;
using System.Globalization;

// 从数据库读取，写入 CSV — 一个文件搞定数据迁移

#:package Quartz

// 使用 Quartz 构建定时任务，部署为单文件后台服务

dotnet project convert app.cs