Added Vanara.Windows.Shell.Taskbar class to get/set information regarding the system taskbar.

UnitTests/Windows.Shell/TaskbarTests.cs

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+using NUnit.Framework;
+using Vanara.PInvoke;
+using Vanara.PInvoke.Tests;
+
+namespace Vanara.Windows.Shell.Tests
+{
+	[TestFixture]
+	public class TaskbarTests
+	{
+		[Test]
+		public void TaskbarTest()
+		{
+			Assert.That(TaskBar.Taskbar.Handle, ResultIs.ValidHandle);
+			Assert.That(TaskBar.Taskbar.Bounds, Is.Not.EqualTo(RECT.Empty));
+			Assert.That(() => TaskBar.Taskbar.AutoHide, Throws.Nothing);
+
+			TestContext.Write($"{TaskBar.Taskbar.Bounds}; {TaskBar.Taskbar.AutoHide}; {TaskBar.Taskbar.Edge}");
+		}
+	}
+}

Windows.Shell.Common/TaskBar/Taskbar.cs

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+using System;
+using Vanara.Extensions;
+using Vanara.PInvoke;
+
+using static Vanara.PInvoke.Shell32;
+
+namespace Vanara.Windows.Shell.TaskBar
+{
+	/// <summary>Provides information about and some control of the system taskbar.</summary>
+	public static class Taskbar
+	{
+		private static bool autoHide, alwaysTop;
+		private static ABE edge;
+		private static HWND hwnd;
+		private static readonly Lazy<bool> isMinWin7 = new(() => PInvokeClientExtensions.IsPlatformSupported(PInvokeClient.Windows7));
+		private static RECT rect;
+
+		/// <summary>
+		/// Gets or sets a value indicating whether the taskbar is always on top. This value is always true for systems since Windows 7.
+		/// </summary>
+		/// <value><see langword="true"/> if always on top; otherwise, <see langword="false"/>.</value>
+		public static bool AlwaysOnTop
+		{
+			get { GetState(); return alwaysTop; }
+			set
+			{
+				if (!isMinWin7.Value)
+				{
+					GetState();
+					if (alwaysTop != value)
+					{
+						alwaysTop = value;
+						SetState();
+					}
+				}
+				else
+					throw new PlatformNotSupportedException();
+			}
+		}
+
+		/// <summary>Gets or sets a value indicating whether the taskbar is configured to automatically hide itself when not used.</summary>
+		/// <value><see langword="true"/> if automatically hidden; otherwise, <see langword="false"/>.</value>
+		public static bool AutoHide
+		{
+			get { GetState(); return autoHide; }
+			set { GetState(); if (autoHide != value) { autoHide = value; SetState(); } }
+		}
+
+		/// <summary>Gets the bounds of the taskbar.</summary>
+		/// <value>The bounds.</value>
+		public static RECT Bounds
+		{
+			get { GetPos(); return rect; }
+			//set { GetPos(); if (rect != value) { rect = value; SetPos(); } }
+		}
+
+		/// <summary>Gets a value that determines on which edge of the screen the taskbar is displayed.</summary>
+		/// <value>The screen edge.</value>
+		public static ABE Edge
+		{
+			get { GetPos(); return edge; }
+			//set { GetPos(); if (edge != value) { edge = value; SetPos(); } }
+		}
+
+		/// <summary>Gets the window handle of the System Taskbar.</summary>
+		/// <value>The window handle.</value>
+		public static HWND Handle
+		{
+			get { GetPos(); return hwnd; }
+		}
+
+		private static void GetPos()
+		{
+			APPBARDATA abd = new(default);
+			Win32Error.ThrowLastErrorIf(SHAppBarMessage(ABM.ABM_GETTASKBARPOS, ref abd), r => r == IntPtr.Zero);
+			rect = abd.rc;
+			edge = abd.uEdge;
+			hwnd = abd.hWnd == default ? User32.FindWindowEx(default, default, "Shell_TrayWnd", null) : abd.hWnd;
+		}
+
+		private static void GetState()
+		{
+			APPBARDATA abd = new(default);
+			ABS state = (ABS)SHAppBarMessage(ABM.ABM_GETSTATE, ref abd).ToInt32();
+			autoHide = state.IsFlagSet(ABS.ABS_AUTOHIDE);
+			alwaysTop = isMinWin7.Value || state.IsFlagSet(ABS.ABS_ALWAYSONTOP);
+		}
+
+		private static void SetPos()
+		{
+			APPBARDATA abd = new(hwnd, 0, edge, rect);
+			SHAppBarMessage(ABM.ABM_SETPOS, ref abd);
+		}
+
+		private static void SetState()
+		{
+			if (hwnd == default)
+			{
+				GetPos();
+			}
+
+			APPBARDATA abd = new(hwnd, lParam: (int)((autoHide ? ABS.ABS_AUTOHIDE : 0) | (alwaysTop ? ABS.ABS_ALWAYSONTOP : 0)));
+			SHAppBarMessage(ABM.ABM_SETSTATE, ref abd);
+		}
+	}
+}