C#应用运行时每3分钟检查数据库连接，断开则终止程序

Hey there! Let's solve your problem of adding periodic database connection checks and auto-terminating the app when the connection fails. Here's a step-by-step solution tailored to your existing code:

WinForms provides a convenient Timer component that runs on the UI thread, which is perfect for your scenario. We'll use it to trigger the connection check every 3 minutes (180,000 milliseconds).

First, let's tweak the CheckIsLocalDAOConnected method to ensure it accurately reflects the current connection state (instead of relying on a static field that might get stale):

namespace CLearning.DataAccess {
    public class DataAccessContext {
        private static bool _isSQLServiceRunning = false;

        // Keep your existing CheckSQLServiceStatus method unchanged

        public static bool CheckIsLocalDAOConnected() {
            try {
                // Test a fresh connection each time for accurate status
                using (var connection = new SqlConnection(GlobalConfig.ConnectionString)) { // Replace with your actual connection string access
                    connection.Open();
                    return true;
                }
            } catch (Exception ex) {
                // Optional: Log exception details for debugging
                Console.WriteLine($"Connection check failed: {ex.Message}");
                return false;
            }
        }
    }
}

Note: I modified this method to create a new connection on each check. If your existing GlobalConfig.Connection.TestConnection() already reliably validates the connection, you can keep that instead of the SqlConnection code above.

Add the timer to your Form1 class to handle periodic checks and app termination:

namespace CLearning {
    public partial class Form1 : Form {
        private System.Windows.Forms.Timer _dbCheckTimer;

        public Form1() {
            InitializeComponent();
            SetupDatabaseCheckTimer();
        }

        private void SetupDatabaseCheckTimer() {
            _dbCheckTimer = new System.Windows.Forms.Timer();
            _dbCheckTimer.Interval = 180000; // 3 minutes in milliseconds
            _dbCheckTimer.Tick += DbCheckTimer_Tick;
            _dbCheckTimer.Start();
        }

        private void DbCheckTimer_Tick(object sender, EventArgs e) {
            // Stop timer during check to avoid overlapping executions
            _dbCheckTimer.Stop();

            bool isConnected = DataAccessContext.CheckIsLocalDAOConnected();
            if (!isConnected) {
                MessageBox.Show(
                    "Database connection has been lost. The application will now terminate.",
                    "Connection Lost",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                
                // Terminate the application gracefully
                Application.Exit();
                // If Application.Exit() doesn't work immediately, use:
                // Environment.Exit(1);
            }

            // Restart timer for next check
            _dbCheckTimer.Start();
        }

        protected override void OnFormClosing(FormClosingEventArgs e) {
            base.OnFormClosing(e);
            // Clean up timer to prevent memory leaks
            _dbCheckTimer?.Stop();
            _dbCheckTimer?.Dispose();
        }
    }
}

Your existing Main method is solid, but we can make a small adjustment for clarity:

namespace CLearning {
    static class Program {
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            // Check SQL Server service status
            bool isServiceRunning = DataAccessContext.CheckSQLServiceStatus();
            if (!isServiceRunning) {
                MessageBox.Show(
                    "SQL Server service could not be started. Application will terminate.",
                    "Service Error",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                return;
            }

            // Initial database connection check
            bool isLocalDAOConnected = DataAccessContext.CheckIsLocalDAOConnected();
            if (!isLocalDAOConnected) {
                MessageBox.Show(
                    "Database connection is not available on the machine. The application will terminate.",
                    "No database connection available",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                return;
            }

            // Launch main form (which handles periodic checks)
            Application.Run(new Form1());
        }
    }
}

Key Notes: #

• Adjust Interval: Change 180000 to a different value if you need a check frequency other than 3 minutes.
• Cleanup: Stopping and disposing the timer on form close prevents memory leaks.
• Connection Accuracy: Testing a fresh connection each time ensures we're checking the current database state, not a stale connection.
• Termination: Application.Exit() closes all forms gracefully. Use Environment.Exit(1) only if you need immediate process termination.

内容的提问来源于stack exchange，提问作者user3094480