方法一:如果程序已经在运行,则直接将运行的程序显示出来
//引入3个命名空间
using System.Runtime.InteropServices;
using System.Diagnostics;
using System.Reflection;
namespace MyWindow
{
static class Program
{
[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>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Process instance = RunningInstance();
if (instance == null)
{
Form1 frm = new Form1();
Application.Run(new Form1());
}
else
{
HandleRunningInstance(instance);
}
}
/// <summary>
/// 获取正在运行的实例,没有运行的实例返回null;
/// </summary>
public static Process RunningInstance()
{
Process current = Process.GetCurrentProcess();
Process[] processes = Process.GetProcessesByName(current.ProcessName);
foreach (Process process in processes)
{
if (process.Id != current.Id)
{
if (Assembly.GetExecutingAssembly().Location.Replace("/", "\\") == current.MainModule.FileName)
{
return process;
}
}
}
return null;
}
/// <summary>
/// 显示已运行的程序。
/// </summary>
public static void HandleRunningInstance(Process instance)
{
ShowWindowAsync(instance.MainWindowHandle, WS_SHOWNORMAL); //显示,可以注释掉
SetForegroundWindow(instance.MainWindowHandle); //放到前端
}
}
}
方法二:如果程序已经在运行,只提示“有程序运行”
System.Threading.Mutex mutex;
bool isNew;
mutex = new System.Threading.Mutex(true, "myproject", out isNew);
if (isNew)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
else
{
MessageBox.Show("本程序已经在运行");
}