如果做到仅仅全屏即可，只需在loaded函数中添加如下代码：

   private void Window_Loaded(object sender, RoutedEventArgs e){// 设置全屏  this.WindowState = System.Windows.WindowState.Normal;this.WindowStyle = System.Windows.WindowStyle.None;this.ResizeMode = System.Windows.ResizeMode.NoResize;this.Topmost = true;this.Left = 0.0;this.Top = 0.0;this.Width = System.Windows.SystemParameters.PrimaryScreenWidth;this.Height = System.Windows.SystemParameters.PrimaryScreenHeight; }

如下文章转自：http://blog.163.com/leingliu@126/blog/static/194762822009524611352/

因为想尝试一下使Wpf应用程序的全屏状态，但是Wpf没有全屏操作的直接实现，在网上搜索一下，发现很多都是使用pinvoke调用win32动态链接库来实现，而且功能也不全，当发现参考文章中的内容时，发现了全屏的简单方法，而且也不用使用Pinvoke，随即修改和完善了功能，代码如下：

using System;
using System.Windows;
using System.Windows.Forms;
using System.Windows.Interop;namespace PhotoViewer
{/// <summary>/// Wpf应用程序全屏辅助类/// /// ——全部使用.Net类进行操作/// ——可进入全屏和退出全屏/// ——可恢复到全屏前的状态/// ——全屏时可切换到其他应用程序/// /// Author:wowin/// Email:leingliu@126.com/// LastUpdate:2009-6-24/// </summary>public static class FullScreenHelper{private static Window _fullWindow;private static WindowState _windowState;private static WindowStyle _windowStyle;private static bool _windowTopMost;private static ResizeMode _windowResizeMode;private static Rect _windowRect;/// <summary>/// 进入全屏/// </summary>/// <param name="window"></param>public static void GoFullscreen(this Window window){//已经是全屏if(window.IsFullscreen()) return;//存储窗体信息_windowState = window.WindowState;_windowStyle = window.WindowStyle;_windowTopMost = window.Topmost;_windowResizeMode = window.ResizeMode;_windowRect.X = window.Left;_windowRect.Y = window.Top;_windowRect.Width = window.Width;_windowRect.Height = window.Height;//变成无边窗体window.WindowState = WindowState.Normal;//假如已经是Maximized，就不能进入全屏，所以这里先调整状态window.WindowStyle = WindowStyle.None;window.ResizeMode = ResizeMode.NoResize;window.Topmost = true;//最大化后总是在最上面//获取窗口句柄 var handle = new WindowInteropHelper(window).Handle;//获取当前显示器屏幕Screen screen = Screen.FromHandle(handle);//调整窗口最大化,全屏的关键代码就是下面3句window.MaxWidth = screen.Bounds.Width;window.MaxHeight = screen.Bounds.Height;window.WindowState = WindowState.Maximized;//解决切换应用程序的问题window.Activated += new EventHandler(window_Activated);window.Deactivated += new EventHandler(window_Deactivated);//记住成功最大化的窗体_fullWindow = window;}static void window_Deactivated(object sender, EventArgs e){var window = sender as Window;window.Topmost = false;}static void window_Activated(object sender, EventArgs e){var window = sender as Window;window.Topmost = true;}/// <summary>/// 退出全屏/// </summary>/// <param name="window"></param>public static void ExitFullscreen(this Window window){//已经不是全屏无操作if (!window.IsFullscreen()) return;//恢复窗口先前信息，这样就退出了全屏window.Topmost = _windowTopMost;window.WindowStyle = _windowStyle;window.ResizeMode = ResizeMode.CanResize;//设置为可调整窗体大小window.Left = _windowRect.Left;window.Width = _windowRect.Width;window.Top = _windowRect.Top;window.Height = _windowRect.Height;window.WindowState = _windowState;//恢复窗口状态信息window.ResizeMode = _windowResizeMode;//恢复窗口可调整信息//移除不需要的事件window.Activated -= window_Activated;window.Deactivated -= window_Deactivated;_fullWindow = null;}/// <summary>/// 窗体是否在全屏状态/// </summary>/// <param name="window"></param>/// <returns></returns>public static bool IsFullscreen(this Window window){if(window==null){throw new ArgumentNullException("window");}return _fullWindow == window;}}
}

还有一个不爽的问题是，在最大化时如果已经是最大化状态，必须先退出最大化状态，造成多闪烁一次，目前还没有找到解决方法。