10个C#程序员经常用到的实用代码片段

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); 

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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; 
} 

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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(“\tPrimary {0}”, screen.Primary); 
   Console.WriteLine(“\tBounds: {0}”, screen.Bounds); 
   Console.WriteLine(“\tWorking Area: {0}”,screen.WorkingArea); 
   Console.WriteLine(“\tBitsPerPixel: {0}”,screen.BitsPerPixel); 
} 

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3 读取注册表键值对

using (RegistryKey keyRun = Registry.LocalMachine.OpenSubKey(@”Software\Microsoft\Windows\CurrentVersion\Run”)) 
{ 
  foreach (string valueName in keyRun.GetValueNames()) 
  { 
   Console.WriteLine(“Name: {0}\tValue: {1}”, valueName, keyRun.GetValue(valueName)); 
  } 
} 

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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(); 

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.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 }); 
} 

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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}\nForced: {1}", verified, !notForced); 

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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(); 

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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。

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); 

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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 ); 

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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 <