Catel - Part 4 of n: Unit testing with Catel

// --------------------------------------------------------------------------------------------------------------------
// <copyright file="FrameworkElementExtensions.cs" company="Catel development team">
//   Copyright (c) 2008 - 2011 Catel development team. All rights reserved.
// </copyright>
// <summary>
//   Extensions for <see cref="System.Windows.FrameworkElement" />.
// </summary>
// --------------------------------------------------------------------------------------------------------------------

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Interop;
using log4net;

namespace Catel.Windows
{
	/// <summary>
	/// Extensions for <see cref="System.Windows.FrameworkElement"/>.
	/// </summary>
	public static class FrameworkElementExtensions
	{
		#region Win32
		[DllImport("user32.dll", SetLastError = true)]
		static extern bool BringWindowToTop(IntPtr hWnd);

		[DllImport("user32.dll", SetLastError = true)]
		static extern bool BringWindowToTop(HandleRef hWnd);

		[DllImport("user32.dll", SetLastError = true)]
		static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);

		[DllImport("user32.dll")]
		static extern IntPtr GetWindowThreadProcessId(IntPtr hWnd, IntPtr ProcessId);

		/// <summary>
		/// The GetForegroundWindow function returns a handle to the foreground window.
		/// </summary>
		[DllImport("user32.dll")]
		static extern IntPtr GetForegroundWindow();

		[DllImport("kernel32.dll")]
		static extern IntPtr GetCurrentThreadId();

		[DllImport("user32.dll", SetLastError = true)]
		static extern bool AttachThreadInput(IntPtr idAttach, IntPtr idAttachTo, bool fAttach);

		[DllImport("user32.dll")]
		static extern IntPtr GetLastActivePopup(IntPtr hWnd);

		[DllImport("user32.dll")]
		static extern IntPtr SetActiveWindow(IntPtr hWnd);
		#endregion

		#region Variables
        /// <summary>
        /// The <see cref="ILog">log</see> object.
        /// </summary>
		private static readonly ILog Log = LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
		#endregion

		#region Methods
		/// <summary>
		/// Activates the window this framework element contains to.
		/// </summary>
		/// <param name="frameworkElement">Reference to the current <see cref="FrameworkElement"/>.</param>
		public static void BringWindowToTop(this FrameworkElement frameworkElement)
		{
			if (frameworkElement == null)
			{
			    return;
			}

			// Check if the framework element has an owner
			Window ownerWindow = null;
			FrameworkElement parentFrameworkElement = frameworkElement;
			while (parentFrameworkElement != null)
			{
				if (parentFrameworkElement is Window)
				{
					ownerWindow = (Window)parentFrameworkElement;
					break;
				}

				parentFrameworkElement = parentFrameworkElement.Parent as FrameworkElement;
			}

			try
			{
				// Get the handle (of the window or process)
				IntPtr windowHandle = (ownerWindow != null) ? new WindowInteropHelper(ownerWindow).Handle :
					Process.GetCurrentProcess().MainWindowHandle;
				if (windowHandle != IntPtr.Zero)
				{
					SetForegroundWindowEx(windowHandle);
				}
			}
			catch (Exception)
			{
			}
		}

		/// <summary>
		/// Get first parent binding group from specified element.
		/// </summary>
		/// <param name="frameworkElement">Reference to the current <see cref="FrameworkElement"/>.</param>
		/// <returns>The first parent BindingGroup or null when not exists.</returns>
		public static System.Windows.Data.BindingGroup GetParentBindingGroup(this FrameworkElement frameworkElement)
		{
			if (frameworkElement == null)
			{
			    return null;
			}

			if (frameworkElement.BindingGroup != null)
			{
			    return frameworkElement.BindingGroup;
			}

			return GetParentBindingGroup(LogicalTreeHelper.GetParent(frameworkElement) as FrameworkElement);
		}

		/// <summary>
		/// Sets the foreground window (some "dirty" win32 stuff).
		/// </summary>
		/// <param name="hWnd">Handle of the window to set to the front.</param>
		/// <remarks>
		/// This method takes over the input thread for the window. This means that you are unable
		/// to debug the code between "Attach" and "Detach" since the input thread of Visual Studio
		/// will be attached to the thread of the application.
		/// </remarks>
		private static void SetForegroundWindowEx(IntPtr hWnd)
		{
			IntPtr foregroundWindowThreadID = GetWindowThreadProcessId(GetForegroundWindow(), IntPtr.Zero);
			IntPtr currentThreadID = GetCurrentThreadId();

			if (!AttachThreadInput(foregroundWindowThreadID, currentThreadID, true))
			{
				Log.Warn(Properties.TraceMessages.AttachThreadInputFailed, Marshal.GetLastWin32Error());
				return;
			}

			IntPtr lastActivePopupWindow = GetLastActivePopup(hWnd);
			SetActiveWindow(lastActivePopupWindow);

			if (!AttachThreadInput(foregroundWindowThreadID, currentThreadID, false))
			{
				Log.Warn(Properties.TraceMessages.DetachThreadInputFailed);
				return;
			}

			BringWindowToTop(hWnd);
		}
		#endregion
	}
}