不同进程之间发送消息将指定界面置顶

实现思路

获取需要被置顶的窗体Handle,将其置顶

 int handle = FindWindow(null, "排号窗口");
  QueueHandle = (int)mystr.dwData;
  //通过句柄
  ShowWindowAsync((IntPtr)handle, 1);


//方式二：或使用如下方式：

//设置窗体状态为默认大小
this.WindowState = FormWindowState.Normal;
//不显示在任务栏
this.ShowInTaskbar = false;

//方式三

[DllImport("user32 ")]
private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

SetParent(this.Handle, (IntPtr)handle);

方式四

this.TopMost = true;

注意：具体使用需根据实际场景决定（可能需要配合使用iiiii）...

具体实现如下：

 #region 获取消息
        /// <summary>
        /// windowapi 通过句柄显示或隐藏窗体函数
        /// </summary>
        /// <param name="hWnd">窗体句柄</param>
        /// <param name="cmdShow">显示类型（0：隐藏窗体，1：默认大小窗体，2：最小化窗体，3：最大化窗体）</param>
        /// <returns>返回成功或失败</returns>
        [DllImport("user32.dll", EntryPoint = "ShowWindowAsync", SetLastError = true)]
        public static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);


        /// <summary>
        /// 0x004A
        /// </summary>
        const int WM_COPYDATA = 0x004A;
        //[StructLayout(LayoutKind.Sequential)]
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }

        protected override void DefWndProc(ref System.Windows.Forms.Message m)
        {
            try
            {
                switch (m.Msg)
                {
                    //  接收自定义消息 USER，并显示其参数
                    case WM_COPYDATA:
                        COPYDATASTRUCT mystr = new COPYDATASTRUCT();
                        Type mytype = mystr.GetType();
                        mystr = (COPYDATASTRUCT)m.GetLParam(mytype);
                        int handle = FindWindow(null, "排号窗口");
                        QueueHandle = (int)mystr.dwData;
                        //通过句柄，最大化窗体
                        ShowWindowAsync((IntPtr)handle, 1);
                        ReceiveMessage = mystr.lpData;
                        ExecuteQueueFlowEvent();
                        break;
                    default:
                        base.DefWndProc(ref m);
                        break;
                }
            }
            catch { return; }
        }

        #endregion

参考：https://www.cnblogs.com/xielong/p/6705243.html?utm_source=itdadao&utm_medium=referral     ——内容很全面谢谢分享