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  • (转)C#程序开发中经常遇到的10条实用的代码

    原文地址:http://www.cnblogs.com/JamesLi2015/p/3147986.html

    1 读取操作系统和CLR的版本 

    OperatingSystem os = System.Environment.OSVersion;

    Console.WriteLine(“Platform: {0}”, os.Platform);

    Console.WriteLine(“Service Pack: {0}”, os.ServicePack);

    Console.WriteLine(“Version: {0}”, os.Version);

    Console.WriteLine(“VersionString: {0}”, os.VersionString);

    Console.WriteLine(“CLR Version: {0}”, System.Environment.Version);

    在我的Windows 7系统中,输出以下信息: 

    Platform: Win32NT

    Service Pack:

    Version: 6.1.7600.0

    VersionString: Microsoft Windows NT 6.1.7600.0

    CLR Version: 4.0.21006.1

    2 读取CPU数量,内存容量 

    可以通过Windows Management Instrumentation (WMI)提供的接口读取所需要的信息。 

    private static UInt32 CountPhysicalProcessors()

    {

        ManagementObjectSearcher objects = new ManagementObjectSearcher(

           “SELECT * FROM Win32_ComputerSystem”);

        ManagementObjectCollection coll = objects.Get();

        foreach(ManagementObject obj in coll)

       {

           return (UInt32)obj[“NumberOfProcessors”];

       }

       return 0;

    }

    private static UInt64 CountPhysicalMemory()

    {

      ManagementObjectSearcher objects =new ManagementObjectSearcher(

         “SELECT * FROM Win32_PhysicalMemory”);

      ManagementObjectCollection coll = objects.Get();

      UInt64 total = 0;

      foreach (ManagementObject obj in coll)

      {

          total += (UInt64)obj[“Capacity”];

       }

       return total;

    }

    请添加对程序集System.Management的引用,确保代码可以正确编译。

    Console.WriteLine(“Machine: {0}”, Environment.MachineName);

    Console.WriteLine(“# of processors (logical): {0}”, Environment.ProcessorCount);

    Console.WriteLine(“# of processors (physical): {0}”  CountPhysicalProcessors());

    Console.WriteLine(“RAM installed: {0:N0} bytes”,  CountPhysicalMemory());

    Console.WriteLine(“Is OS 64-bit? {0}”,   Environment.Is64BitOperatingSystem);

    Console.WriteLine(“Is process 64-bit? {0}”,  Environment.Is64BitProcess);

    Console.WriteLine(“Little-endian: {0}”, BitConverter.IsLittleEndian);

    foreach (Screen screen in  System.Windows.Forms.Screen.AllScreens)

    {

        Console.WriteLine(“Screen {0}”, screen.DeviceName);

        Console.WriteLine(“ Primary {0}”, screen.Primary);

        Console.WriteLine(“ Bounds: {0}”, screen.Bounds);

        Console.WriteLine(“ Working Area: {0}”,screen.WorkingArea);

        Console.WriteLine(“ BitsPerPixel: {0}”,screen.BitsPerPixel);

    }

    3 读取注册表键值对 

    using (RegistryKey keyRun = Registry.LocalMachine.OpenSubKey(@”SoftwareMicrosoftWindowsCurrentVersionRun”))

    {

       foreach (string valueName in keyRun.GetValueNames())

       {

        Console.WriteLine(“Name: {0} Value: {1}”, valueName, keyRun.GetValue(valueName));

       }

    请添加命名空间Microsoft.Win32,以确保上面的代码可以编译。

    4 启动,停止Windows服务 

    这项API提供的实用功能常常用来管理应用程序中的服务,而不必到控制面板的管理服务中进行操作。 

    ServiceController controller = new ServiceController(“e-M-POWER”);     

    controller.Start();     

    if (controller.CanPauseAndContinue)      

    {     

       controller.Pause();     

       controller.Continue();     

    }     

    controller.Stop();

    .net提供的API中,可以实现一句话安装与卸载服务 

    if (args[0] == "/i")

    {

          ManagedInstallerClass.InstallHelper(new string[] { Assembly.GetExecutingAssembly().Location });

    }

    else if (args[0] == "/u")

    {

      ManagedInstallerClass.InstallHelper(new string[] { "/u", Assembly.GetExecutingAssembly().Location });

    如代码所示,给应用程序传入i或u参数,以表示是卸载或是安装程序。

    5 验证程序是否有strong name (P/Invoke) 

    比如在程序中,为了验证程序集是否有签名,可调用如下方法 

    [DllImport("mscoree.dll", CharSet=CharSet.Unicode)]

    static extern bool StrongNameSignatureVerificationEx(string wszFilePath, bool fForceVerification, ref bool pfWasVerified);

    bool notForced = false;

    bool verified = StrongNameSignatureVerificationEx(assembly, false, ref notForced);

    Console.WriteLine("Verified: {0} Forced: {1}", verified, !notForced);

    这个功能常用在软件保护方法,可用来验证签名的组件。即使你的签名被人去掉,或是所有程序集的签名都被去除,只要程序中有这一项调用代码,则可以停止程序运行。

    6 响应系统配置项的变更 

    比如我们锁定系统后,如果QQ没有退出,则它会显示了忙碌状态。

    请添加命名空间Microsoft.Win32,然后对注册下面的事件。 

    . DisplaySettingsChanged (包含Changing) 显示设置

    . InstalledFontsChanged 字体变化

    . PaletteChanged

    . PowerModeChanged 电源状态

    . SessionEnded (用户正在登出或是会话结束)

    . SessionSwitch (变更当前用户)

    . TimeChanged 时间改变

    . UserPreferenceChanged (用户偏号 包含Changing)

    我们的ERP系统,会监测系统时间是否改变,如果将时间调整后ERP许可文件之外的范围,会导致ERP软件不可用。

    7 运用Windows7的新特性 

    Windows7系统引入一些新特性,比如打开文件对话框,状态栏可显示当前任务的进度。 

    Microsoft.WindowsAPICodePack.Dialogs.CommonOpenFileDialog ofd = new Microsoft.WindowsAPICodePack.Dialogs.CommonOpenFileDialog();

    ofd.AddToMostRecentlyUsedList = true;

    ofd.IsFolderPicker = true;

    ofd.AllowNonFileSystemItems = true;

    ofd.ShowDialog();

    用这样的方法打开对话框,与BCL自带类库中的OpenFileDialog功能更多一些。不过只限于Windows 7系统中,所以要调用这段代码,还要检查操作系统的版本要大于6,并且添加对程序集Windows API Code Pack for Microsoft®.NET Framework的引用,请到这个地址下载 http://code.msdn.microsoft.com/WindowsAPICodePack

    8 检查程序对内存的消耗 

    用下面的方法,可以检查.NET给程序分配的内存数量 

    long available = GC.GetTotalMemory(false);

    Console.WriteLine(“Before allocations: {0:N0}”, available);

    int allocSize = 40000000;

    byte[] bigArray = new byte[allocSize];

    available = GC.GetTotalMemory(false);

    Console.WriteLine(“After allocations: {0:N0}”, available);

    在我的系统中,它运行的结果如下所示 

    Before allocations: 651,064

    After allocations: 40,690,080

    使用下面的方法,可以检查当前应用程序占用的内存 

    Process proc = Process.GetCurrentProcess();

    Console.WriteLine(“Process Info: “+Environment.NewLine+

    “Private Memory Size: {0:N0}”+Environment.NewLine +

    “Virtual Memory Size: {1:N0}” + Environment.NewLine +

    “Working Set Size: {2:N0}” + Environment.NewLine +

    “Paged Memory Size: {3:N0}” + Environment.NewLine +

    “Paged System Memory Size: {4:N0}” + Environment.NewLine +

     “Non-paged System Memory Size: {5:N0}” + Environment.NewLine,

    proc.PrivateMemorySize64,   proc.VirtualMemorySize64,  proc.WorkingSet64,  proc.PagedMemorySize64, proc.PagedSystemMemorySize64,  proc.NonpagedSystemMemorySize64 );

    9 使用记秒表检查程序运行时间 

    如果你担忧某些代码非常耗费时间,可以用StopWatch来检查这段代码消耗的时间,如下面的代码所示 

    System.Diagnostics.Stopwatch timer = new System.Diagnostics.Stopwatch();

    timer.Start();

    Decimal total = 0;

    int limit = 1000000;

    for (int i = 0; i < limit; ++i)

    {

         total = total + (Decimal)Math.Sqrt(i);

    }

    timer.Stop();

    Console.WriteLine(“Sum of sqrts: {0}”,total);

    Console.WriteLine(“Elapsed milliseconds: {0}”,

    timer.ElapsedMilliseconds);

    Console.WriteLine(“Elapsed time: {0}”, timer.Elapsed);

    现在已经有专门的工具来检测程序的运行时间,可以细化到每个方法,比如dotNetPerformance软件。

    以上面的代码为例子,您需要直接修改源代码,如果是用来测试程序,则有些不方便。请参考下面的例子。 

    class AutoStopwatch : System.Diagnostics.Stopwatch, IDisposable

    {

      public AutoStopwatch()

      {

          Start();

      }

      public void Dispose()

      {

          Stop();

          Console.WriteLine(“Elapsed: {0}”, this.Elapsed);

      }

    }

    借助于using语法,像下面的代码所示,可以检查一段代码的运行时间,并打印在控制台上。 

    using (new AutoStopwatch())

    {

       Decimal total2 = 0;

       int limit2 = 1000000;

       for (int i = 0; i < limit2; ++i)

       {

          total2 = total2 + (Decimal)Math.Sqrt(i);

       }

    }

    10 使用光标 

    当程序正在后台运行保存或是册除操作时,应当将光标状态修改为忙碌。可使用下面的技巧。 

    class AutoWaitCursor : IDisposable

    {

    private Control _target;

    private Cursor _prevCursor = Cursors.Default;

    public AutoWaitCursor(Control control)

    {

      if (control == null)

      {

        throw new ArgumentNullException(“control”);

      }

      _target = control;

      _prevCursor = _target.Cursor;

      _target.Cursor = Cursors.WaitCursor;

    }

    public void Dispose()

    {

      _target.Cursor = _prevCursor;

    }

    }

    用法如下所示,这个写法,是为了预料到程序可能会抛出异常 

    using (new AutoWaitCursor(this))

    {

    ...

    throw new Exception();

    }

    如代码所示,即使抛出异常,光标也可以恢复到之间的状态。

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  • 原文地址:https://www.cnblogs.com/tlduck/p/5202682.html
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