refactor: 项目稳定性优化

MainForm.cs

@@ -7,9 +7,9 @@ namespace TimerApp
 {
     public partial class MainForm : Form
     {
-        private ActivityMonitor _monitor;
+        private ActivityMonitor _monitor = null!;
         private AppSettings _settings;
-        private RestForm _restForm;
+        private RestForm? _restForm;
 
         // Colors
         private Color _darkBg = Color.FromArgb(30, 30, 30);
@@ -106,8 +106,8 @@ namespace TimerApp
             // Manual input validation
             txtWork.KeyPress += ValidateDigitInput;
             txtRest.KeyPress += ValidateDigitInput;
-            txtWork.Leave += (s, ev) => ValidateRange((TextBox)s, 1, 120);
-            txtRest.Leave += (s, ev) => ValidateRange((TextBox)s, 1, 30);
+            txtWork.Leave += (s, ev) => ValidateRange((TextBox)s!, 1, 120);
+            txtRest.Leave += (s, ev) => ValidateRange((TextBox)s!, 1, 30);
 
             // Focus handling (remove custom caret)
             txtWork.KeyDown += TextBox_KeyDown;
@@ -163,7 +163,7 @@ namespace TimerApp
             }
         }
 
-        private void ValidateDigitInput(object sender, KeyPressEventArgs e)
+        private void ValidateDigitInput(object? sender, KeyPressEventArgs e)
         {
             // Allow control keys (backspace, etc.) and digits
             if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
@@ -216,7 +216,7 @@ namespace TimerApp
 
         // CustomCaret removed to use system caret with centered text
 
-        private void TextBox_KeyDown(object sender, KeyEventArgs e)
+        private void TextBox_KeyDown(object? sender, KeyEventArgs e)
         {
             if (e.KeyCode == Keys.Enter)
             {
@@ -407,11 +407,11 @@ namespace TimerApp
             _monitor.IdleThreshold = TimeSpan.FromSeconds(_settings.IdleThresholdSeconds);
         }
 
-        private void Monitor_StateChanged(object sender, EventArgs e)
+        private void Monitor_StateChanged(object? sender, EventArgs e)
         {
             if (InvokeRequired)
             {
-                Invoke(new Action<object, EventArgs>(Monitor_StateChanged), sender, e);
+                Invoke(new Action<object?, EventArgs>(Monitor_StateChanged), sender, e);
                 return;
             }
             UpdateStatusUI();
@@ -456,11 +456,11 @@ namespace TimerApp
             }
         }
 
-        private void Monitor_WorkProgressChanged(object sender, TimeSpan remaining)
+        private void Monitor_WorkProgressChanged(object? sender, TimeSpan remaining)
         {
             if (InvokeRequired)
             {
-                Invoke(new Action<object, TimeSpan>(Monitor_WorkProgressChanged), sender, remaining);
+                Invoke(new Action<object?, TimeSpan>(Monitor_WorkProgressChanged), sender, remaining);
                 return;
             }
             lblTimeLeft.Text = $"{remaining.Minutes:D2}:{remaining.Seconds:D2}";
@@ -476,11 +476,11 @@ namespace TimerApp
             }
         }
 
-        private void Monitor_RestStarted(object sender, EventArgs e)
+        private void Monitor_RestStarted(object? sender, EventArgs e)
         {
             if (InvokeRequired)
             {
-                Invoke(new Action<object, EventArgs>(Monitor_RestStarted), sender, e);
+                Invoke(new Action<object?, EventArgs>(Monitor_RestStarted), sender, e);
                 return;
             }
 
@@ -494,13 +494,13 @@ namespace TimerApp
             _restForm.Show();
         }
 
-        private void RestForm_SkipRequested(object sender, EventArgs e)
+        private void RestForm_SkipRequested(object? sender, EventArgs e)
         {
             _monitor.Stop();
             _monitor.Start();
         }
 
-        private void Monitor_RestProgressChanged(object sender, TimeSpan remaining)
+        private void Monitor_RestProgressChanged(object? sender, TimeSpan remaining)
         {
             if (_restForm != null && !_restForm.IsDisposed && _restForm.Visible)
             {
@@ -508,11 +508,11 @@ namespace TimerApp
             }
         }
 
-        private void Monitor_RestEnded(object sender, EventArgs e)
+        private void Monitor_RestEnded(object? sender, EventArgs e)
         {
             if (InvokeRequired)
             {
-                Invoke(new Action<object, EventArgs>(Monitor_RestEnded), sender, e);
+                Invoke(new Action<object?, EventArgs>(Monitor_RestEnded), sender, e);
                 return;
             }
 
@@ -555,12 +555,12 @@ namespace TimerApp
             }
         }
 
-        private void notifyIcon1_MouseDoubleClick(object sender, MouseEventArgs e)
+        private void notifyIcon1_MouseDoubleClick(object? sender, MouseEventArgs e)
         {
             ShowForm();
         }
 
-        private void toolStripMenuItemShow_Click(object sender, EventArgs e)
+        private void toolStripMenuItemShow_Click(object? sender, EventArgs e)
         {
             ShowForm();
         }