（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(“\tPrimary {0}”, screen.Primary);

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

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

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

}

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));

}

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}\nForced: {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);