如何运行c#WinForm应用程序的一个实例? [英] How to run one instance of a c# WinForm application?

问题描述

我有一个C#应用程序，该应用程序在启动时显示登录表单，并在验证用户身份后显示主表单.我使用Mutex来限制我的应用程序只能运行一个实例.而且，这仅适用于登录"表单.一旦显示主表单，它就不会限制用户重新打开登录"表单.我正在寻找一种解决方案，一旦打开主窗体，就无法显示登录"屏幕.

I've a C# application that displays a login form when launched and displays the main form after users are authenticated. I used Mutex to restrict that only one instance of my application runs. And, this works fine for only the Login form. Once the main form is displayed, it doesn't restrict users from reopening the Login form. I was looking for a solution by which the Login screen couldn't be displayed once the main form is already opened.

这是我的Program.cs

Here is my Program.cs

 [STAThread]
    static void Main()
    {
        bool mutexCreated=true;

        using (Mutex mutex = new Mutex(true, "eCS", out mutexCreated))
        {
            if (mutexCreated)
            {
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Login());
            }
            else
            {
                Process current = Process.GetCurrentProcess();
                foreach (Process process in Process.GetProcessesByName(current.ProcessName))
                {
                    if (process.Id != current.Id)
                    {
                        XtraMessageBox.Show("Another instance of eCS is already running.", "eCS already running", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        SetForegroundWindow(process.MainWindowHandle);
                        break;
                    }
                }
            }
        }
    }

推荐答案

我做了一些小改动:

namespace CSMutex
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            bool mutexCreated=true;
            using(Mutex mutex = new Mutex(true, "eCS", out mutexCreated))
            {
                if (mutexCreated)
                {
                    Application.EnableVisualStyles();
                    Application.SetCompatibleTextRenderingDefault(false);
                    Login loging = new Login();
                    Application.Run(loging);
                    Application.Run(new Main() { UserName = loging.UserName });
                }
                else
                {
                    Process current = Process.GetCurrentProcess();
                    foreach (Process process in Process.GetProcessesByName(current.ProcessName))
                    {
                        if (process.Id != current.Id)
                        {
                            MessageBox.Show("Another instance of eCS is already running.", "eCS already running", MessageBoxButtons.OK, MessageBoxIcon.Information);
                            //SetForegroundWindow(process.MainWindowHandle);
                            break;
                        }
                    }
                }
            }
        }
    }
}

可以按预期工作-即即使关闭Login表单(并且启动了主应用程序表单)，它也不允许用户再次运行该应用程序. 我决定不从Login内部创建Main(这是我相信您的应用程序的工作方式)，而是将参数传递给Main. 我还对Login做了一些小的更改，因此它具有UserName属性(与Main相同).

That works as expected - i.e. even when Login form is closed (and the main application form is started) it doesn't let user run the application once again. I've decided not to create Main from within Login (this is I believe how you application works) and instead I am passing parameter to Main. I have also made some small change to Login so it has UserName propert (same as Main).

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