Using Edit and Continue in Visual Studio 2022 to Apply Code Changes While Debugging

Desired outcome

Make a code change during a debugging session and see the effect immediately, without stopping the debugger, rebuilding the solution, or restarting the application.

Prerequisites

• Visual Studio 2022 (or later) with the .NET desktop development workload installed.
• The solution must be built in Debug configuration.
• Edit and Continue enabled: Debug → Options → General → Enable Edit and Continue (checkbox).
• You have write permission to the source files of the project you are debugging.

Procedure

1. Open the solution in Visual Studio and set a breakpoint at the line you intend to modify (e.g., inside a method that runs repeatedly). Press F5 to start debugging.
2. When the breakpoint hits, locate the statement you want to change in the editor. For example, change a string literal:

   // Before edit
   Console.WriteLine("Hello");
   // After edit
   Console.WriteLine("Hello from Edit and Continue");
   

3. Apply the edit:
   • Press Ctrl+S to save the file, or click the Apply Code Changes button that appears in the toolbar when Edit and Continue is active.
4. Continue execution with F5 (or F10/F11 for step‑through). The debugger will insert the new IL at runtime and resume without a full rebuild.

Expected checks

• The modified line executes and the new output appears (e.g., the console shows "Hello from Edit and Continue").
• Breakpoints that were set before the edit remain active and are hit as expected.
• The Locals and Watch windows display values that reflect the changed code.
• Open the Output window, filter to "Edit and Continue"; you should see a message like "Edit and Continue: applied changes" and no error messages.

Recovery options (if the edit is not supported)

Visual Studio will display a warning dialog when an unsupported change is attempted (e.g., adding a new method, changing a method signature, or modifying an async/await state). In that case:

1. Revert the edit immediately (Ctrl+Z) to return to the last successfully applied state.
2. If you have already accepted the unsupported edit, stop debugging (Shift+F5), rebuild the solution, and start a new debugging session.
3. As a fallback, disable Edit and Continue (Debug → Options → General → Enable Edit and Continue unchecked) and use the standard edit‑compile‑debug cycle.

Limitations and practical verification

• Structural changes (adding/removing types, modifying method signatures, changing accessibility) generally require a restart.
• Native C++ projects support Edit and Continue only when using the Microsoft native debugger and the /Zi compiler flag is set.
• Mixed‑mode debugging (managed + native) or active profiling tools may automatically disable the feature.
• To verify that Edit and Continue is active, look for the lightning‑bolt icon next to the Apply Code Changes button in the toolbar; if it is disabled, the feature is not available for the current session.