WCF作为一种比较新的技术工具,其中有许多东西值得我们去深入学习。比如WCF附加属性。我们在这里就为大家介绍一下WCF附加属性实现单实例的方法。#t#
WCF附加属性代码如下:
- class SingletonWindow
- {
- //注册附加属性
- public static readonly DependencyProperty
IsEnabledProperty = - DependencyProperty.RegisterAttached
("IsEnabled", typeof(bool), typeof
(SingletonWindow), new Framework
PropertyMetadata(OnIsEnabledChanged)); - public static void SetIsEnabled
(DependencyObject element, Boolean value) - {
- element.SetValue(IsEnabledProperty, value);
- }
- public static Boolean GetIsEnabled
(DependencyObject element) - {
- return (Boolean)element.GetValue
(IsEnabledProperty); - }
- //根据附加属性的返回值使能单实例模式
- public static void OnIsEnabledChanged
(DependencyObject obj, Dependency
PropertyChangedEventArgs args) - {
- if ((bool)args.NewValue != true)
- {
- return;
- }
- Process();
- return;
- }
- public static void Process()
//如果不适用附加属性也可以直接使用此函数 - {
- //判断单实例的方式有很多,如mutex,process,
文件锁等,这里用的是process方式 - var process = GetRunningInstance();
- if (process != null)
- {
- HandleRunningInstance(process);
- Environment.Exit(0);
- }
- }
- const int WS_SHOWNORMAL = 1;
- [System.Runtime.InteropServices.
DllImport("User32.dll")] - static extern bool ShowWindowAsync
(IntPtr hWnd, int cmdShow); - [System.Runtime.InteropServices.
DllImport("User32.dll")] - static extern bool SetForeground
Window(IntPtr hWnd); - [System.Runtime.InteropServices.
DllImport("user32.dll")] - static extern bool FlashWindow
(IntPtr hWnd,bool bInvert); - static System.Diagnostics.Process
GetRunningInstance() - {
- var current = System.Diagnostics.
Process.GetCurrentProcess(); - var processes = System.Diagnostics
.Process.GetProcessesByName(current.
ProcessName); - foreach (var process in processes)
- {
- if (process.Id != current.Id)
- if (System.Reflection.Assembly.
GetExecutingAssembly().Location.
Replace("/", "\\") == current.
MainModule.FileName) - return process;
- }
- return null;
- }
- static void HandleRunningInstance
(System.Diagnostics.Process instance) - {
- if (instance.MainWindowHandle!=IntPtr.Zero)
- {
- for (int i = 0; i < 2; i++)
- {
- FlashWindow(instance.MainWindowHandle, 500);
- }
- SetForegroundWindow(instance.
MainWindowHandle); - ShowWindowAsync(instance.
MainWindowHandle, WS_SHOWNORMAL); - }
- else
- {
- //else 处理有点麻烦,简化如下
- MessageBox.Show("已经有一个实例在运行,
无法启动第二个实例"); - }
- }
- static void FlashWindow(IntPtr hanlde, int interval)
- {
- FlashWindow(hanlde, true);
- System.Threading.Thread.Sleep(interval);
- FlashWindow(hanlde, false);
- System.Threading.Thread.Sleep(interval);
- }
- }
WCF附加属性代码其实很简单,前半部分是注册依赖属性,然后根据依赖属性判断是否启用单实例模式;后半部分就是一个传统的单实例模式的功能了。也就不介绍了。
使用这段WCF附加属性代码也很简单:
Xaml方式:在主窗口的xaml文件中加入附加属性即可
- < Window xmlns:src=
"clr-namespace:WpfApplication1"
src:SingletonWindow.IsEnabled="true">
传统方式:直接使用代码中后半部分,和winform下没什么区别。在主窗口的构造函数里面加入这句话。
SingletonWindow.Process();