能否编程调用Visual Studio的JSON转C#类功能用于预构建步骤？

Great question! Let’s break this down clearly, since there’s a small but important distinction between VS’s paste feature and your goal of converting JSON Schema to C# classes for pre-build automation.

First, a quick clarification: VS’s "Edit → Paste Special → Paste JSON as Classes" is built to generate C# classes from raw JSON instances, not directly from JSON Schema. That said, if your end goal is JSON Schema → C# classes (which you specified), Microsoft has mature official tools for this—and if you still want to reuse VS’s internal logic for automation, there are workable paths to do that too.

Option 1: Official, Stable Tools for JSON Schema → C# Classes #

Skip hacking VS’s internal code and use Microsoft’s supported tools instead—these are designed explicitly for automation like pre-build steps:

• dotnet-svcutil: This is Microsoft’s official service reference tool that supports JSON Schema to C# class generation. Install it as a global .NET tool first:

  dotnet tool install --global dotnet-svcutil
  

  Then add a pre-build command to your project (via .csproj or VS’s pre-build event settings) to run it:

  dotnet svcutil path/to/your/schema.json --output-dir GeneratedClasses
  

• System.Text.Json Source Generators (with Schema): For .NET 6+, System.Text.Json includes native JSON Schema support. You can define a validation context tied to your schema, and use Roslyn source generators to auto-generate the corresponding C# classes at build time. This is lightweight and integrates directly into the .NET build pipeline.

Option 2: Reusing VS's "Paste JSON as Classes" Logic #

If you specifically want to leverage the exact logic behind VS’s paste feature, know that it’s built on Roslyn (the .NET compiler platform) and JSON parsing libraries—but it doesn’t have a public, supported API. That said, you can:

• Reference VS Internal Packages: You can add NuGet references to packages like Microsoft.VisualStudio.LanguageServices and Microsoft.VisualStudio.Web.CodeGeneration.Core (note: these are intended for VS extension development, not general use, and may break between VS versions). Look for internal classes like JsonClassGenerator which power the paste feature.
• Replicate the Logic Yourself: VS’s class generation logic is straightforward to mimic with Roslyn. Here’s the core workflow:
  1. Parse your JSON (instance or schema) using Newtonsoft.Json or System.Text.Json.
  2. Use Roslyn’s syntax tree APIs to construct C# class declarations, properties, and fields matching the JSON structure.
  3. Save the generated syntax tree to a .cs file in your project.
     This approach is more stable than relying on internal VS APIs, since you control the full implementation.

Setting Up Pre-Build Automation #

Whichever option you choose, wire it into your project’s pre-build steps via the .csproj file for consistent, automated generation:

<Target Name="GenerateJsonSchemaClasses" BeforeTargets="PreBuildEvent">
  <!-- Replace with your chosen tool/script command -->
  <Exec Command="dotnet svcutil $(SolutionDir)Schemas/MyApiSchema.json --output-dir $(ProjectDir)Generated" />
</Target>

This will run the class generation automatically every time you build your project.

内容的提问来源于stack exchange，提问作者Stiefel