Changes to handle changes in Notepad that allows multiple documents.

Author: bstordrup

src/Serilog.Sinks.Notepad/Sinks/Notepad/Interop/NotepadTextWriter.cs

@@ -123,10 +123,10 @@ private static IntPtr FindNotepadEditorHandle(IntPtr notepadWindowHandle)
             }
 
             // Issue #59 - Alternate way of finding the RichEditD2DPT class:
-            if (FindEditorHandleThroughChildWindows(notepadWindowHandle) is var childRichEditHandle
-                && childRichEditHandle != IntPtr.Zero)
+            if (FindEditorHandleThroughChildWindows(notepadWindowHandle) is var richEditHandleFromChildren
+                && richEditHandleFromChildren != IntPtr.Zero)
             {
-                return childRichEditHandle;
+                return richEditHandleFromChildren;
             }
 
             return User32.FindWindowEx(notepadWindowHandle, IntPtr.Zero, "Edit", null);
@@ -140,6 +140,13 @@ private void EnsureNotDisposed()
             }
         }
 
+        private static string GetClassNameFromWindow(IntPtr handle)
+        {
+            StringBuilder sb = new StringBuilder(256);
+            var ret = User32.GetClassName(handle, sb, sb.Capacity);
+            return ret != 0 ? sb.ToString() : string.Empty;
+        }
+
         private static bool EnumWindow(IntPtr handle, IntPtr pointer)
         {
             GCHandle gch = GCHandle.FromIntPtr(pointer);
@@ -149,18 +156,20 @@ private static bool EnumWindow(IntPtr handle, IntPtr pointer)
                 throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
             }
 
-            // We only want windows of class RichEditD2DPT.
-            if (User32.FindWindowEx(handle, IntPtr.Zero, "RichEditD2DPT", null) != IntPtr.Zero)
+            if (string.Equals(GetClassNameFromWindow(handle), "RichEditD2DPT", StringComparison.OrdinalIgnoreCase))
             {
                 list.Add(handle);
+
+                // Stop enumerating - we found the one.
+                return false;
             }
 
             return true;
         }
 
         private static IntPtr FindEditorHandleThroughChildWindows(IntPtr notepadWindowHandle)
         {
-            List<IntPtr> result = new List<IntPtr>();
+            List<IntPtr> result = new List<IntPtr>(1);
             GCHandle listHandle = GCHandle.Alloc(result);
             try
             {

src/Serilog.Sinks.Notepad/Sinks/Notepad/Interop/User32.cs

@@ -37,14 +37,15 @@ internal class User32
         public static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam);
 
 
-        [DllImport("user32.dll")]
-        public static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);
-
         // Needed for EnumChildWindows for registering a call back function.
         public delegate bool Win32Callback(IntPtr hwnd, IntPtr lParam);
 
-        [DllImport("user32.Dll")]
+        [DllImport("user32.Dll", CharSet = CharSet.Unicode, SetLastError = true)]
         [return: MarshalAs(UnmanagedType.Bool)]
         public static extern bool EnumChildWindows(IntPtr parentHandle, Win32Callback callback, IntPtr lParam);
+
+        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+        public static extern int GetClassName(IntPtr hWnd, System.Text.StringBuilder lpClassName, int nMaxCount);
+
     }
 }