[C#] 如何激活窗口

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using System.Diagnostics;

namespace activeexternalappwindowtest
{

    public partial class Form1 : Form
    {
        [DllImport("user32.dll")]
        private static extern bool
        SetForegroundWindow(IntPtr hWnd);
        [DllImport("user32.dll")]
        private static extern bool ShowWindowAsync(IntPtr   hWnd, int nCmdShow);
        [DllImport("user32.dll")]
        private static extern bool IsIconic(IntPtr hWnd);
        // 消息函数
        [DllImport("user32.dll", EntryPoint = "PostMessageA")]
        public static extern bool PostMessage(IntPtr hWnd, int Msg, int wParam, int lParam);

        [DllImport("user32.dll")]
        public static extern IntPtr FindWindow(string strclassName, string strWindowName);
        [DllImportAttribute("user32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);

        public const int WM_SYSCOMMAND = 0x0112;
        public const int SC_MAXIMIZE = 0xF030;

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Process[] processes = Process.GetProcessesByName("csi");

           
            if (processes.Length > 0)
            {
                IntPtr hWnd = processes[0].MainWindowHandle;

                //  if (IsIconic(hWnd))
                //    ShowWindowAsync(hWnd, 9);// 9就是SW_RESTORE标志，表示还原窗体
                SendMessage(hWnd, WM_SYSCOMMAND, SC_MAXIMIZE, 0);
                SetForegroundWindow(hWnd);
            }

        }
    }
}