WPF App.xaml.cs常用模板，包括：异常捕获，App只能启动一次

app.xaml.cs中的代码每次都差不多，故特地将其整理出来直接复用：

  5 using system;
  6 using system.configuration;
  7 using system.diagnostics;
  8 using system.globalization;
  9 using system.net;
 10 using system.net.sockets;
 11 using system.reflection;
 12 using system.runtime.interopservices;
 13 using system.windows;
 14 
 15 namespace wpfdemo
 16 {
 17     /// <summary>
 18     /// app.xaml 的交互逻辑
 19     /// </summary>
 20     public partial class app : application
 21     {
 22         private loginwindow login = new loginwindow();
 23         private ilog logger;
 24 
 25         static app()
 26         {
 27             log4net.config.xmlconfigurator.configure();
 28         }
 29 
 30         public app()
 31         {
 32             logger = logmanager.getlogger(typeof(this));
 33         }
 34 
 35         system.threading.mutex _mutex;
 36         protected override void onstartup(startupeventargs e)
 37         {
 38             assembly assembly = assembly.getexecutingassembly();
 39             string mutexname = string.format(cultureinfo.invariantculture, "local\\{{{0}}}{{{1}}}", assembly.gettype().guid, assembly.getname().name);
 40             bool ret = false;
 41             _mutex = new system.threading.mutex(true, mutexname, out ret);
 42             if (!ret)
 43             {
 44                 this.logger.info("已经运行程序，激活至主窗口.");
 45                 handlerunninginstance();
 46                 environment.exit(0);
 47                 return;
 48             }
 49 
 50             base.onstartup(e);
 51             this.logger.info("app startup.");
 52             this.shutdownmode = system.windows.shutdownmode.onexplicitshutdown;
 53 
 54             appdomain.currentdomain.unhandledexception += currentdomain_unhandledexception;
 55             this.dispatcherunhandledexception += app_dispatcherunhandledexception;
 56 
 57             this.login.show();
 58         }
 59 
 60         void currentdomain_unhandledexception(object sender, unhandledexceptioneventargs e)
 61         {
 62             try
 63             {
 64                 var exception = e.exceptionobject as exception;
 65                 if (exception != null)
 66                 {
 67                     this.logger.fatalformat("非ui线程全局异常, message:{0}, error: {1}", exception.message, exception.tostring());
 68                 }
 69             }
 70             catch (exception ex)
 71             {
 72                 this.logger.fatalformat("非ui线程全局异常, message:{0}, error: {1}", ex.message, ex.tostring());
 73             }
 74         }
 75 
 76         void app_dispatcherunhandledexception(object sender, system.windows.threading.dispatcherunhandledexceptioneventargs e)
 77         {
 78             try
 79             {
 80                 e.handled = true;
 81                 this.logger.fatalformat("ui线程全局异常：meassage:{0}, error: {1}", e.exception.message, e.exception.tostring());
 82             }
 83             catch (exception ex)
 84             {
 85                 this.logger.fatalformat("ui线程全局异常：meassage:{0}, error: {1}", ex.message, ex.tostring());
 86             }
 87         }
 88 
 89         
 90         protected override void onexit(exiteventargs e)
 91         {
 92             this.logger.info("app exit.");
 93             
 94             base.onexit(e);
 95         }
 96 
 97         ///<summary>
 98         /// 该函数设置由不同线程产生的窗口的显示状态
 99         /// </summary>
100         /// <param name="hwnd">窗口句柄</param>
101         /// <param name="cmdshow">指定窗口如何显示。查看允许值列表，请查阅showwlndow函数的说明部分</param>
102         /// <returns>如果函数原来可见，返回值为非零；如果函数原来被隐藏，返回值为零</returns>
103         [dllimport("user32.dll")]
104         private static extern bool showwindowasync(intptr hwnd, int cmdshow);
105 
106         /// <summary>
107         ///  该函数将创建指定窗口的线程设置到前台，并且激活该窗口。键盘输入转向该窗口，并为用户改各种可视的记号。
108         ///  系统给创建前台窗口的线程分配的权限稍高于其他线程。 
109         /// </summary>
110         /// <param name="hwnd">将被激活并被调入前台的窗口句柄</param>
111         /// <returns>如果窗口设入了前台，返回值为非零；如果窗口未被设入前台，返回值为零</returns>
112         [dllimport("user32.dll")]
113         private static extern bool setforegroundwindow(intptr hwnd);
114 
115         static process runninginstance()
116         {
117             process current = process.getcurrentprocess();
118             process[] processes = process.getprocessesbyname(current.processname);
119             foreach (process process in processes)
120             {
121                 if (process.id != current.id)
122                 {
123                     if (process.mainmodule.filename == current.mainmodule.filename)
124                     {
125                         return process;
126                     }
127                 }
128             }
129             return null;
130         }
131 
132         private const int sw_normal = 1;     //正常弹出窗体
133         private const int sw_maximize = 3;     //最大化弹出窗体
134 
135         public static void handlerunninginstance()
136         {
137             var instance = runninginstance();
138             if (instance != null)
139             {
140                 showwindowasync(instance.mainwindowhandle, sw_normal);
141                 setforegroundwindow(instance.mainwindowhandle);
142             }
143         }
144     }
145 }