将ASP.NET 4.7/Razor 3.0项目迁移至ASP.NET Core 2.0（Linux环境）

Hey there, I’ve helped folks tackle this exact scenario before—migrating old ASP.NET apps to Core without a Windows environment. Let’s walk through practical, Linux-native steps to get this done:

First, Get Your Tooling Set Up #

• Install the .NET Core 2.0 SDK on your Linux distro. For Debian/Ubuntu-based systems, run:

  wget -q https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
  sudo dpkg -i packages-microsoft-prod.deb
  sudo apt-get update
  sudo apt-get install dotnet-sdk-2.0
  

  Adjust the commands if you’re using RHEL/CentOS or another distro.
• In VS Code, install the C# Dev Kit and ASP.NET Core Tools extensions—these will give you intellisense, debugging, and project scaffolding support.

Step-by-Step Migration (Manual is More Reliable Than Auto-Convert) #

Auto-conversion tools (like the ones in Visual Studio Windows) don’t play well on Linux, so we’ll build a new Core project and migrate code piece by piece:

1. Scaffold a Fresh ASP.NET Core 2.0 Razor Pages Project
   Open your terminal, navigate to your work directory, and run:

   dotnet new razor -n MyMigratedSite
   cd MyMigratedSite
   

   This creates the standard Core Razor Pages structure (Pages folder, appsettings.json, Startup.cs) which you’ll build on.

2. Migrate Razor Views & Layouts

   • Copy your old .cshtml views from the original project’s Views folder to the new project’s Pages folder.
   • Move your _Layout.cshtml and shared partials to Pages/Shared (Core uses this instead of Views/Shared).
   • Critical: Linux is case-sensitive! Make sure your file names match references in code (e.g., if your view references _Layout.cshtml, don’t rename it to _layout.cshtml).

3. Port Business Logic & Models

   • Copy your old .cs files (Models, custom helpers, business logic) to the new project’s Models or Services folder.
   • Update namespaces to match the new project (e.g., change OldSite.Models to MyMigratedSite.Models).
   • Replace any references to System.Web with Core equivalents:
     • System.Web.HttpContext.Current → Use dependency injection with IHttpContextAccessor (inject it in Razor pages with @inject IHttpContextAccessor HttpContextAccessor).
     • System.Web.Configuration.WebConfigurationManager → Use IConfiguration from Core’s dependency injection.

4. Migrate Configuration

   • Replace your old web.config settings with appsettings.json. For example, a connection string would go from:

     <connectionStrings>
       <add name="MyDb" connectionString="..." />
     </connectionStrings>
     

     To this in appsettings.json:

     "ConnectionStrings": {
       "MyDb": "..."
     }
     

   • Add any custom app settings to appsettings.json as key-value pairs.

5. Fix NuGet Dependencies

   • Remove any System.Web-related packages from your old project—they won’t work in Core.
   • Add Core-compatible packages via the terminal:

     dotnet add package Microsoft.AspNetCore.Session  # If you use session state
     dotnet add package Microsoft.EntityFrameworkCore.SqlServer  # For DB access
     

6. Configure Startup.cs

   • Add essential services to ConfigureServices:

     public void ConfigureServices(IServiceCollection services)
     {
         services.AddRazorPages();
         services.AddSession(); // Enable session if needed
         services.AddHttpContextAccessor(); // For accessing HttpContext
         // Add DB context, authentication, etc., here
     }
     

   • Update the Configure method to use middleware:

     public void Configure(IApplicationBuilder app, IHostingEnvironment env)
     {
         if (env.IsDevelopment())
         {
             app.UseDeveloperExceptionPage();
         }
         else
         {
             app.UseExceptionHandler("/Error");
             app.UseHsts();
         }
     
         app.UseHttpsRedirection();
         app.UseStaticFiles();
         app.UseSession(); // Add this before UseRouting if using session
         app.UseRouting();
         app.UseAuthorization();
         app.UseEndpoints(endpoints =>
         {
             endpoints.MapRazorPages();
         });
     }
     

Linux-Specific Tips #

• File Permissions: Ensure your project directory has read/write permissions for the user running the app:

  chmod -R 755 MyMigratedSite
  

• Debugging in VS Code: Use the built-in debugger (F5) to catch runtime errors. The C# extension will auto-generate a launch.json file for you.
• Testing Locally: Run dotnet run in your project directory to start the app, then visit https://localhost:5001 to test pages.

Troubleshooting Common Issues #

• Missing Namespaces: Use VS Code’s "Quick Fix" (Ctrl+. on Linux) to auto-add required using statements for Core APIs.
• View Compilation Errors: Ensure all Razor pages have the correct @page directive at the top (required for Core Razor Pages).
• Session Not Working: Double-check that app.UseSession() comes before app.UseRouting() in Startup.cs.

内容的提问来源于stack exchange，提问作者TemporalBeing