(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。

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