如果你是一个C#程序员,那么本文介绍的10个C#常用代码片段一定会给你带来帮助,从底层的资源操作,到上层的UI应用,这些代码也许能给你的开发节省不少时间。以下是原文:
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);
- 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。
来源:51CTO