migrating-mvc-filters

name	migrating-mvc-filters
description	Migrates ASP.NET MVC global filters (GlobalFilterCollection, HandleErrorAttribute, FilterConfig) to ASP.NET Core exception handling middleware and filter pipeline. Use when upgrading MVC apps that register filters via GlobalFilters.Filters.Add(), have a FilterConfig.cs, use HandleErrorAttribute, or need to convert custom IActionFilter/IExceptionFilter implementations to ASP.NET Core equivalents. Also triggers for global error handling migration, MVC-to-Core filter conversion, and UseExceptionHandler setup.
metadata	{"traits":".NET|CSharp|VisualBasic|DotNetCore","discovery":"lazy"}

ASP.NET MVC Global Filters Migration

Overview

Migrate GlobalFilterCollection-based filters from ASP.NET MVC to ASP.NET Core middleware and filter pipeline. ASP.NET Core replaces HandleErrorAttribute with UseExceptionHandler middleware because middleware runs earlier in the pipeline and catches errors from all middleware, not just controller actions.

Workflow

Track progress across these steps:

Migration Progress:
- [ ] Step 1: Identify main controller from routing
- [ ] Step 2: Add exception handler middleware
- [ ] Step 3: Add error action methods
- [ ] Step 4: Create error views
- [ ] Step 5: Convert custom filters
- [ ] Step 6: Remove FilterConfig and GlobalFilters references

Step 1: Identify Main Controller

Determine the main controller name from routing configuration. Check Program.cs for route registration first, then fall back to RouteConfig.cs if the project hasn't been fully migrated. The default route typically maps to HomeController. This controller will host the error-handling action methods.