C# winform 只运行一个应用程序

应用程序只有一个实例，当启动一次时创建实例，当多次启用时激活当前实例。 

创建一个单利管理类

using Microsoft.VisualBasic.ApplicationServices;
public class AppContainer : WindowsFormsApplicationBase
{
public AppContainer()
 { 
 IsSingleInstance = true;
 EnableVisualStyles = true;
 ShutdownStyle = ShutdownMode.AfterMainFormCloses;
 }

protected override void OnCreateMainForm()
 {
 MainForm = new Form1();
 }
}

在Program.cs中添加如下代码

static class Program
{
/// <summary>
/// 应用程序的主入口点。
/// </summary>
 [STAThread]
static void Main()
 {
AppContainer app = new AppContainer();
 app.Run(Environment.GetCommandLineArgs());
 }
}

 

第二版的实现：

 

using System.Threading;
using System.Runtime.InteropServices;
static class Program
{
#region 第二版
static Mutex mutex = new Mutex(true, "{FFAB7D56-89DB-4059-8465-4EB852326633}"); 
#endregion

/// <summary>
/// 应用程序的主入口点。
/// </summary>
 [STAThread]
static void Main()
 {
#region 第一版
//AppContainer app = new AppContainer();
//app.Run(Environment.GetCommandLineArgs());
#endregion

#region 第二版
if (mutex.WaitOne(TimeSpan.Zero, true))
 {
 Application.EnableVisualStyles();
 Application.SetCompatibleTextRenderingDefault(false);
 Application.Run(new Form1());
 }
else
 {
 NativeMethods.PostMessage((IntPtr)NativeMethods.HWND_BROADCAST,NativeMethods.WM_SHOW, IntPtr.Zero,IntPtr.Zero);
 }
#endregion
 }
}
#region 第二版
internal class NativeMethods
{
public const int HWND_BROADCAST = 0xffff;
public static readonly int WM_SHOW = RegisterWindowMessage("WM_SHOWME");
 [DllImport("user32")]
public static extern bool PostMessage(IntPtr hwnd, int msg, IntPtr wparam, IntPtr lparam);
 [DllImport("user32")]
public static extern int RegisterWindowMessage(string message);
} 
#endregion

 

public partial class Form1 : Form
{
public Form1()
 {
 InitializeComponent();
 }

#region 第二版
protected override void WndProc(ref Message m)
 {
if (m.Msg == NativeMethods.WM_SHOW)
 {
if (WindowState == FormWindowState.Minimized)
 {
 WindowState = FormWindowState.Normal;
 }
bool top = TopMost;
 TopMost = true;
 TopMost = top;
 }
base.WndProc(ref m);
 }
#endregion
}

 

 

参考资料：https://www.codeproject.com/Articles/12890/Single-Instance-C-Application-for-NET-2-0

                  https://*.com/questions/19147/what-is-the-correct-way-to-create-a-single-instance-application