wiform实现单个应用程序，并可以激活

最新推荐文章于 2025-08-23 10:15:27 发布

转载最新推荐文章于 2025-08-23 10:15:27 发布 · 86 阅读

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原文链接：http://www.cnblogs.com/sqshine/archive/2008/12/03/1346608.html

本文介绍了一种通过枚举窗口并激活已有实例的方法来确保应用程序仅运行一个实例的技术。该技术适用于Windows平台，并提供了具体的C#代码示例。

Code
public class SingleApplication
    {
        private const int SW_RESTORE = 9;
        private static string sTitle;
        private static IntPtr windowHandle;

        /// <summary>
        /// Imports
        /// </summary>
        [DllImport("user32.Dll")]
        private static extern int EnumWindows(EnumWinCallBack callBackFunc, int lParam);

        [DllImport("User32.Dll")]
        private static extern void GetWindowText(int hWnd, StringBuilder str, int nMaxCount);

        [DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]
        private static extern bool SetForegroundWindow(IntPtr hWnd);

        [DllImport("user32.dll")]
        private static extern Boolean ShowWindow(IntPtr hWnd, Int32 nCmdShow);

        /// <summary>
        /// EnumWindowCallBack
        /// </summary>
        /// <param name="hwnd"></param>
        /// <param name="lParam"></param>
        /// <returns></returns>
        private static bool EnumWindowCallBack(int hwnd, int lParam)
        {
            windowHandle = (IntPtr) hwnd;

            StringBuilder sbuilder = new StringBuilder(256);
            GetWindowText((int) windowHandle, sbuilder, sbuilder.Capacity);
            string strTitle = sbuilder.ToString();

            if (strTitle == sTitle)
            {
                ShowWindow(windowHandle, SW_RESTORE);
                SetForegroundWindow(windowHandle);
                return false;
            }
            return true;
        } //EnumWindowCallBack

        /// <summary>
        /// Execute a form base application if another instance already running on
        /// the system activate previous one
        /// </summary>
        /// <param name="frmMain">main form</param>
        /// <returns>true if no previous instance is running</returns>
        public static bool Run(Form frmMain)
        {
            sTitle = frmMain.Text;

            if (EnumWindows(EnumWindowCallBack, 0) == 0)
            {
                return false;
            }
            Application.Run(frmMain);
            return true;
        }

        public static bool Run(string frmText)
        {
            sTitle = frmText;

            if (EnumWindows(EnumWindowCallBack, 0) == 0)
            {
                return false;
            }
            return true;
        }

        /// <summary>
        ///
        /// </summary>
        /// <returns></returns>
        public static bool Run()
        {
            Process pr = Process.GetCurrentProcess();
            string strProcessName = pr.ProcessName;
            if (Process.GetProcessesByName(strProcessName).Length > 1)
            {
                return false;
            }
            return true;
        }

        #region Nested type: EnumWinCallBack

        private delegate bool EnumWinCallBack(int hwnd, int lParam);

        #endregion
    }

调用方式：

if (SingleApplication.Run( " Form1 " )) // Form1为应用程序入口窗体
Application.Run( new Form1());

// 或者
// if (SingleApplication.Run(new Form1().Text)) // Form1为应用程序入口窗体
// Application.Run(new Form1());

// 或者
// SingleApplication.Run(new Form1())

转载于:https://www.cnblogs.com/sqshine/archive/2008/12/03/1346608.html