WinForm 应用程序禁止多个进程运行

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Diagnostics;
using System.Reflection;
using System.Runtime.InteropServices;

namespace 开启新的进程
{
static class Program
{
/// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
System.Diagnostics.Process instance = RunningInstance();
if (instance == null)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
else
{
HandleRunningInstance(instance);
}
}

/// <summary>
/// 获取当前正在运行的进程实例
/// </summary>
/// <returns></returns>
public static Process RunningInstance()
{
// 获取当前活动的进程
Process current = Process.GetCurrentProcess();
// 获取当前本地计算机上指定的进程名称的所有进程
Process[] processes = Process.GetProcessesByName(current.ProcessName);
foreach (Process process in processes)
{
// 忽略当前进程
if (process.Id != current.Id)
{
if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName)
{
return process;
}
}
}

// 如果没有其他同名进程存在,则返回 null
return null;
}

// 指示该属性化方法由非托管动态链接库 (DLL) 作为静态入口点公开
[DllImport("User32.dll")]
private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
[DllImport("User32.dll")]
private static extern bool SetForegroundWindow(IntPtr hWnd);
private const int WS_SHOWNORMAL = 1;

/// <summary>
/// 如果有另一个同名进程启动,则调用之前的实例
/// </summary>
/// <param name="instance"></param>
private static void HandleRunningInstance(Process instance)
{
// 确保窗体不是最小化或者最大化
ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL);
// 将之前启动的进程实例弄到前台窗口
SetForegroundWindow(instance.MainWindowHandle);
}
}
}