Added extension methods and some minor related refactoring.

Switched from WindowManager to extensible WindowSeekers (derived from BaseWindowSeeker).
Window seeking by title implemented and command line parameter added.

OnTopReplica/EnumerableExtensions.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace OnTopReplica {
+    /// <summary>
+    /// Extension methods for IEnumerable.
+    /// </summary>
+    static class EnumerableExtensions {
+
+        /// <summary>
+        /// Gets the first element of an enumeration of a default value.
+        /// </summary>
+        public static T FirstOrDefault<T>(this IEnumerable<T> collection) {
+            if (collection == null)
+                throw new ArgumentNullException();
+
+            using (var enumerator = collection.GetEnumerator()) {
+                if (!enumerator.MoveNext())
+                    return default(T);
+                else
+                    return enumerator.Current;
+            }
+        }
+
+    }
+}

OnTopReplica/MainForm.cs

@@ -9,6 +9,7 @@ using System.Collections.Generic;
 using OnTopReplica.Native;
 using OnTopReplica.Update;
 using OnTopReplica.StartupOptions;
+using OnTopReplica.WindowSeekers;
 
 namespace OnTopReplica {
 
@@ -20,7 +21,7 @@ namespace OnTopReplica {
         Panel _sidePanelContainer;
 
         //Managers
-        WindowManager _windowManager = new WindowManager();
+        BaseWindowSeeker _windowSeeker = new TaskWindowSeeker();
         MessagePumpManager _msgPumpManager = new MessagePumpManager();
         UpdateManager _updateManager = new UpdateManager();
 
@@ -105,6 +106,8 @@ namespace OnTopReplica {
         protected override void OnHandleCreated(EventArgs e){
  	        base.OnHandleCreated(e);
 
+            _windowSeeker.OwnerHandle = this.Handle;
+
             //Platform specific form initialization
             Program.Platform.InitForm(this);
         }
@@ -372,7 +375,8 @@ namespace OnTopReplica {
                 _thumbnailPanel.SetThumbnailHandle(handle);
 
 #if DEBUG
-                Console.WriteLine("Cloning window HWND {0}.", handle.Handle);
+                string windowClass = WindowMethods.GetWindowClass(handle.Handle);
+                Console.WriteLine("Cloning window HWND {0} of class {1}.", handle.Handle, windowClass);
 #endif
 
                 if (region.HasValue)

OnTopReplica/MainForm_MenuEvents.cs

@@ -29,8 +29,9 @@ namespace OnTopReplica {
         }
 
         private void Menu_Windows_opening(object sender, CancelEventArgs e) {
-            _windowManager.Refresh(WindowManager.EnumerationMode.TaskWindows);
-            WindowListHelper.PopulateMenu(this, _windowManager, (ToolStrip)sender,
+            _windowSeeker.Refresh();
+            var menu = (ToolStrip)sender;
+            menu.PopulateMenu(this, _windowSeeker,
                 CurrentThumbnailWindowHandle, new EventHandler(Menu_Windows_itemclick));
         }
 

OnTopReplica/Native/WindowMethods.cs

@@ -37,6 +37,17 @@ namespace OnTopReplica.Native {
                 return String.Empty;
         }
 
+        const int MaxClassLength = 255;
+
+        public static string GetWindowClass(IntPtr hwnd) {
+            var sb = new StringBuilder(MaxClassLength + 1);
+            RealGetWindowClass(hwnd, sb, MaxClassLength);
+            return sb.ToString();
+        }
+
+        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+        static extern uint RealGetWindowClass(IntPtr hwnd, [Out] StringBuilder lpString, uint maxCount);
+
         public enum WindowLong {
             WndProc = (-4),
             HInstance = (-6),

OnTopReplica/OnTopReplica.csproj

@@ -112,6 +112,7 @@
     </Compile>
     <Compile Include="CloneClickEventArgs.cs" />
     <Compile Include="CloseRequestEventArgs.cs" />
+    <Compile Include="EnumerableExtensions.cs" />
     <Compile Include="ExtensionAttribute.cs" />
     <Compile Include="MainForm_Features.cs">
       <SubType>Form</SubType>
@@ -134,6 +135,10 @@
     <Compile Include="Native\HookMethods.cs" />
     <Compile Include="Native\HotKeyMethods.cs" />
     <Compile Include="Native\HT.cs" />
+    <Compile Include="Pair.cs" />
+    <Compile Include="WindowSeekers\BaseWindowSeeker.cs" />
+    <Compile Include="WindowSeekers\ByTitleWindowSeeker.cs" />
+    <Compile Include="WindowSeekers\TaskWindowSeeker.cs" />
     <None Include="Native\ITaskBarList.cs" />
     <Compile Include="Native\MessagingMethods.cs" />
     <Compile Include="Native\MK.cs" />
@@ -273,7 +278,6 @@
     <Compile Include="Win32Helper.cs" />
     <Compile Include="WindowHandle.cs" />
     <Compile Include="WindowListHelper.cs" />
-    <Compile Include="WindowManager.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Assets\windows.png" />

OnTopReplica/OnTopReplica.csproj.user

@@ -16,6 +16,6 @@
     <EnableSecurityDebugging>false</EnableSecurityDebugging>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|AnyCPU'">
-    <StartArguments>/windowId=459572 /r=20,20,100,80</StartArguments>
+    <StartArguments>/windowClass="OperaWindowClass"</StartArguments>
   </PropertyGroup>
 </Project>

OnTopReplica/Pair.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace OnTopReplica {
+
+    /// <summary>
+    /// Simple tuple with two values.
+    /// </summary>
+    struct Pair<T1, T2> {
+        public T1 Item1;
+        public T2 Item2;
+    }
+
+}

OnTopReplica/SidePanels/GroupSwitchPanel.cs

@@ -4,6 +4,7 @@ using System.Windows.Forms;
 using OnTopReplica.Properties;
 using System.Collections.Generic;
 using OnTopReplica.MessagePumpProcessors;
+using OnTopReplica.WindowSeekers;
 
 namespace OnTopReplica.SidePanels {
 	partial class GroupSwitchPanel : SidePanel {
@@ -23,8 +24,8 @@ namespace OnTopReplica.SidePanels {
         }
 
         private void LoadWindowList() {
-            var manager = new WindowManager();
-            manager.Refresh(WindowManager.EnumerationMode.TaskWindows);
+            var manager = new TaskWindowSeeker();
+            manager.Refresh();
 
             var imageList = new ImageList();
             imageList.ColorDepth = ColorDepth.Depth32Bit;

OnTopReplica/StartupOptions/Options.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using System.Drawing;
 using System.IO;
+using OnTopReplica.WindowSeekers;
 
 namespace OnTopReplica.StartupOptions {
 
@@ -94,7 +95,12 @@ namespace OnTopReplica.StartupOptions {
                 handle = WindowHandle.FromHandle(WindowId.Value);
             }
             else if (WindowTitle != null) {
-                //TODO
+                var seeker = new ByTitleWindowSeeker(WindowTitle) {
+                    OwnerHandle = form.Handle
+                };
+                seeker.Refresh();
+
+                handle = seeker.Windows.FirstOrDefault();
             }
             else if (WindowClass != null) {
                 //TODO

OnTopReplica/WindowListHelper.cs

@@ -3,8 +3,12 @@ using System.Collections.Generic;
 using System.Text;
 using System.Windows.Forms;
 using OnTopReplica.Properties;
+using OnTopReplica.WindowSeekers;
 
 namespace OnTopReplica {
+    /// <summary>
+    /// Extension methods used to apply a window list to a menu.
+    /// </summary>
 	static class WindowListHelper {
 
         public class WindowSelectionData {
@@ -14,7 +18,15 @@ namespace OnTopReplica {
 
 		const int MaxWindowTitleLength = 55;
 
-		public static void PopulateMenu(Form ownerForm, WindowManager windowManager, ToolStrip menu,
+        /// <summary>
+        /// Populates the menu with a list of windows.
+        /// </summary>
+        /// <param name="menu">The menu to populate.</param>
+        /// <param name="ownerForm">The owning form.</param>
+        /// <param name="windowManager">The window manager that provides the windows list.</param>
+        /// <param name="currentHandle">The currently used window (will be checked in the list).</param>
+        /// <param name="clickHandler">Event handler for clicks on window items.</param>
+		public static void PopulateMenu(this ToolStrip menu, Form ownerForm, BaseWindowSeeker windowManager,
                                         WindowHandle currentHandle, EventHandler clickHandler) {
             var regions = GetRegions();
 

OnTopReplica/WindowManager.cs

@@ -1,104 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-using OnTopReplica.Native;
-
-namespace OnTopReplica {
-	/// <summary>A helper class that allows you to easily build and keep a list of Windows (in the form of WindowHandle objects).</summary>
-	public class WindowManager {
-        
-        List<WindowHandle> _windows = new List<WindowHandle>();
-
-		public enum EnumerationMode {
-			/// <summary>All windows with 'Visible' flag.</summary>
-			AllVisible,
-
-			/// <summary>All top level windows.</summary>
-			AllTopLevel,
-
-			/// <summary>Windows of a task (like Alt+Tab).</summary>
-			TaskWindows
-		}
-
-		/// <summary>Refreshes the window list.</summary>
-		public void Refresh(EnumerationMode mode) {
-            _windows = new List<WindowHandle>();
-
-            WindowManagerMethods.EnumWindowsProc proc = null;
-			switch (mode) {
-				case EnumerationMode.AllVisible:
-                    proc = new WindowManagerMethods.EnumWindowsProc(EnumWindowProcAll);
-					break;
-
-				case EnumerationMode.AllTopLevel:
-                    proc = new WindowManagerMethods.EnumWindowsProc(EnumWindowProcTopLevel);
-					break;
-
-				case EnumerationMode.TaskWindows:
-                    proc = new WindowManagerMethods.EnumWindowsProc(EnumWindowProcTask);
-					break;
-			}
-
-			WindowManagerMethods.EnumWindows(proc, IntPtr.Zero);
-		}
-
-
-		public IEnumerable<WindowHandle> Windows {
-			get {
-                return _windows;
-			}
-		}
-
-
-
-		private bool EnumWindowProcAll(IntPtr hwnd, IntPtr lParam) {
-            if (WindowManagerMethods.IsWindowVisible(hwnd)) {
-                string title = WindowMethods.GetWindowText(hwnd);
-				_windows.Add( new WindowHandle(hwnd, title));
-			}
-			return true;
-		}
-
-		private bool EnumWindowProcTopLevel(IntPtr hwnd, IntPtr lParam) {
-            if (WindowManagerMethods.IsWindowVisible(hwnd)) {
-				//Check if window has no parent
-                if ((long)WindowManagerMethods.GetParent(hwnd) == 0 && WindowManagerMethods.GetDesktopWindow() != hwnd) {
-                    string title = WindowMethods.GetWindowText(hwnd);
-					_windows.Add( new WindowHandle(hwnd, title));
-				}
-			}
-			return true;
-		}
-
-		private bool EnumWindowProcTask(IntPtr hwnd, IntPtr lParam) {
-			//Code taken from: http://www.thescarms.com/VBasic/alttab.aspx
-
-			//Accept windows that
-			// - are visible
-			// - do not have a parent
-			// - have no owner and are not Tool windows OR
-			// - have an owner and are App windows
-
-			//Reject empty titles
-
-			string title = WindowMethods.GetWindowText(hwnd);
-			if (string.IsNullOrEmpty(title))
-				return true;
-
-            if (WindowManagerMethods.IsWindowVisible(hwnd)) {
-                if ((long)WindowManagerMethods.GetParent(hwnd) == 0) {
-                    bool hasOwner = (long)WindowManagerMethods.GetWindow(hwnd, WindowManagerMethods.GetWindowMode.GW_OWNER) != 0;
-                    WindowMethods.WindowExStyles exStyle = (WindowMethods.WindowExStyles)WindowMethods.GetWindowLong(hwnd, WindowMethods.WindowLong.ExStyle);
-
-                    if (((exStyle & WindowMethods.WindowExStyles.ToolWindow) == 0 && !hasOwner) || //unowned non-tool window
-                        ((exStyle & WindowMethods.WindowExStyles.AppWindow) == WindowMethods.WindowExStyles.AppWindow && hasOwner)) { //owned application window
-						_windows.Add(new WindowHandle(hwnd, title));
-					}
-				}
-			}
-
-			return true;
-		}
-
-	}
-}

OnTopReplica/WindowSeekers/BaseWindowSeeker.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OnTopReplica.Native;
+
+namespace OnTopReplica.WindowSeekers {
+    
+    /// <summary>
+    /// Base class for window seekers that can populate a list of window handles based on some criteria.
+    /// </summary>
+    abstract class BaseWindowSeeker {
+
+        List<WindowHandle> _list = new List<WindowHandle>();
+
+        /// <summary>
+        /// Get the matching windows from the last refresh.
+        /// </summary>
+        public IEnumerable<WindowHandle> Windows {
+            get {
+                return _list;
+            }
+        }
+
+        /// <summary>
+        /// Forces a window list refresh.
+        /// </summary>
+        public virtual void Refresh() {
+            _list.Clear();
+
+            WindowManagerMethods.EnumWindows(
+                new WindowManagerMethods.EnumWindowsProc(RefreshCallback),
+                IntPtr.Zero);
+        }
+
+        private bool RefreshCallback(IntPtr hwnd, IntPtr lParam) {
+            bool cont = true;
+
+            //Skip owner
+            if (hwnd == OwnerHandle)
+                return true;
+
+            //Extract basic properties
+            string title = WindowMethods.GetWindowText(hwnd);
+
+            if (InspectWindow(hwnd, title, ref cont)) {
+                //Window has been picked
+                _list.Add(new WindowHandle(hwnd, title));
+            }
+
+            return cont;
+        }
+
+        /// <summary>
+        /// Inspects a window and returns whether the window should be listed or not.
+        /// </summary>
+        /// <param name="hwnd">Handle of the window.</param>
+        /// <param name="title">Title of the window (if any).</param>
+        /// <param name="terminate">Indicates whether the inspection loop should terminate after this window.</param>
+        /// <returns>True if the window should be listed.</returns>
+        protected abstract bool InspectWindow(IntPtr hwnd, string title, ref bool terminate);
+
+        /// <summary>
+        /// Gets or sets the window handle of the owner.
+        /// </summary>
+        /// <remarks>
+        /// Windows with this handle will be automatically skipped.
+        /// </remarks>
+        public IntPtr OwnerHandle { get; set; }
+
+    }
+
+}

OnTopReplica/WindowSeekers/ByTitleWindowSeeker.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OnTopReplica.Native;
+
+namespace OnTopReplica.WindowSeekers {
+    /// <summary>
+    /// Seeks a single window by approximately matching its title.
+    /// </summary>
+    /// <remarks>
+    /// Title search is case-insensitive and matches only the beginning of the windows' titles.
+    /// </remarks>
+    class ByTitleWindowSeeker : BaseWindowSeeker {
+
+        public ByTitleWindowSeeker(string titleSeekString) {
+            if (titleSeekString == null)
+                throw new ArgumentNullException();
+
+            TitleMatch = titleSeekString.Trim().ToLower();
+        }
+
+        public string TitleMatch { get; private set; }
+
+        protected override bool InspectWindow(IntPtr hwnd, string title, ref bool terminate) {
+            //Skip empty titles
+            if (string.IsNullOrEmpty(title))
+                return false;
+
+            //Skip non-top-level windows (skips most internal controls)
+            bool hasParent = (long)WindowManagerMethods.GetParent(hwnd) != 0;
+            bool hasOwner = (long)WindowManagerMethods.GetWindow(hwnd, WindowManagerMethods.GetWindowMode.GW_OWNER) != 0;
+            if (hasParent || hasOwner)
+                return false;
+
+            var modTitle = title.Trim().ToLower();
+            if (modTitle.StartsWith(TitleMatch)) {
+                terminate = true; //only one needed
+                return true;
+            }
+
+            return false;
+        }
+
+    }
+}

OnTopReplica/WindowSeekers/TaskWindowSeeker.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OnTopReplica.Native;
+
+namespace OnTopReplica.WindowSeekers {
+    class TaskWindowSeeker : BaseWindowSeeker {
+        
+        protected override bool InspectWindow(IntPtr hwnd, string title, ref bool terminate) {
+            //Code taken from: http://www.thescarms.com/VBasic/alttab.aspx
+
+            //Accept windows that
+            // - are visible
+            // - do not have a parent
+            // - have no owner and are not Tool windows OR
+            // - have an owner and are App windows
+
+            //Reject empty titles
+
+            if (string.IsNullOrEmpty(title))
+                return false;
+
+            if (WindowManagerMethods.IsWindowVisible(hwnd)) {
+                if ((long)WindowManagerMethods.GetParent(hwnd) == 0) {
+                    bool hasOwner = (long)WindowManagerMethods.GetWindow(hwnd, WindowManagerMethods.GetWindowMode.GW_OWNER) != 0;
+                    WindowMethods.WindowExStyles exStyle = (WindowMethods.WindowExStyles)WindowMethods.GetWindowLong(hwnd, WindowMethods.WindowLong.ExStyle);
+
+                    if (((exStyle & WindowMethods.WindowExStyles.ToolWindow) == 0 && !hasOwner) || //unowned non-tool window
+                        ((exStyle & WindowMethods.WindowExStyles.AppWindow) == WindowMethods.WindowExStyles.AppWindow && hasOwner)) { //owned application window
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
+    }
+}