How Can I Handle Console Application Exit Events in C#?

Graceful Shutdown in C# Console Applications: Handling Exit Events

Multi-threaded C# console applications require robust cleanup procedures upon termination to ensure proper resource management. While .NET doesn't offer a built-in exit event, we can leverage the Win32 API for a reliable solution.

The Absence of a Direct .NET Event

Unfortunately, the .NET framework lacks a direct event for detecting application exit.

Utilizing the Win32 API: A Practical Approach

The Win32 API's SetConsoleCtrlHandler function provides a mechanism to register a handler for various control signals, including console closure. This allows for executing custom code before the application terminates.

Code Example: Implementing a Console Exit Handler

The following code snippet demonstrates registering a handler for console close events:

<code class="language-csharp">using System;
using System.Runtime.InteropServices;

// ... other using statements ...

public class Program
{
    [DllImport("Kernel32.dll")]
    private static extern bool SetConsoleCtrlHandler(HandlerRoutine handler, bool add);

    private delegate bool HandlerRoutine(CtrlTypes ctrlType);

    private enum CtrlTypes
    {
        CTRL_C_EVENT = 0,
        CTRL_BREAK_EVENT = 1,
        CTRL_CLOSE_EVENT = 2,
        CTRL_LOGOFF_EVENT = 5,
        CTRL_SHUTDOWN_EVENT = 6
    }

    private static bool Handler(CtrlTypes ctrlType)
    {
        Console.WriteLine("Console exit event detected: " + ctrlType);
        // Perform cleanup operations here (e.g., closing files, stopping threads)
        return true; // Indicate that the handler processed the event
    }

    public static void Main(string[] args)
    {
        SetConsoleCtrlHandler(Handler, true);
        // ... your application's main logic ...
        Console.ReadKey(); // Keep the console open until a key is pressed
    }
}</code>

Important Considerations and Limitations:

This approach relies on the Windows API and may not be directly portable to non-Windows environments. The Handler function should perform all necessary cleanup tasks, such as closing files, releasing resources, and ensuring thread termination before returning true. Returning false indicates that the default system handler should be invoked. Remember to handle potential exceptions within the Handler function.

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