fix(debugger): only notify on actual breakpoint hits, not step operations

Use IDebugBreakpointEvent2 instead of DBGMODE_Break to detect when a
breakpoint is hit. This prevents the notification from firing on every
step (F10/F11) operation.

Fixes #2

Author: CalvinAllen

src/CodingWithCalvin.BreakpointNotifier/DebuggerEvents.cs

@@ -1,12 +1,14 @@
-using System.Windows.Forms;
+using System;
+using System.Windows.Forms;
 using Microsoft;
 using Microsoft.VisualStudio;
+using Microsoft.VisualStudio.Debugger.Interop;
 using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Shell.Interop;
 
 namespace CodingWithCalvin.BreakpointNotifier
 {
-    public sealed class DebuggerEvents : IVsDebuggerEvents
+    public sealed class DebuggerEvents : IVsDebuggerEvents, IDebugEventCallback2
     {
         private DebuggerEvents()
         {
@@ -16,6 +18,7 @@ private DebuggerEvents()
                 ServiceProvider.GlobalProvider.GetService(typeof(IVsDebugger));
             Assumes.Present(debugger);
             debugger.AdviseDebuggerEvents(this, out _);
+            debugger.AdviseDebugEventCallback(this);
         }
 
         public static DebuggerEvents Initialize()
@@ -25,11 +28,23 @@ public static DebuggerEvents Initialize()
 
         public int OnModeChange(DBGMODE dbgmodeNew)
         {
-            switch (dbgmodeNew)
+            // No longer showing message here - we use IDebugEventCallback2 instead
+            // to specifically detect breakpoint hits vs. step operations
+            return VSConstants.S_OK;
+        }
+
+        public int Event(
+            IDebugEngine2 pEngine,
+            IDebugProcess2 pProcess,
+            IDebugProgram2 pProgram,
+            IDebugThread2 pThread,
+            IDebugEvent2 pEvent,
+            ref Guid riidEvent,
+            uint dwAttrib)
+        {
+            if (pEvent is IDebugBreakpointEvent2)
             {
-                case DBGMODE.DBGMODE_Break:
-                    MessageBox.Show("Breakpoint Hit!");
-                    break;
+                MessageBox.Show("Breakpoint Hit!");
             }
 
             return VSConstants.S_OK;