using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Diagnostics;

using System.Runtime.InteropServices;



namespace CSharpWin04

{

    public partial class Form3 : Form

    {

        public Form3()

        {

            InitializeComponent();

        }



        Process pcalc = null;

        //启动计算器

        private void button1_Click(object sender, EventArgs e)

        {

            pcalc = Process.Start("calc.exe");

        }



        //获取文本框的结果

        [DllImport("user32.dll", EntryPoint = "FindWindow")]

        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]

        public static extern IntPtr FindWindowEx(IntPtr hWnd1, IntPtr hWnd2, string lpsz1, string lpsz2);

        [DllImport("User32 ")]

        public static extern bool SendMessage(IntPtr hWnd, int Msg, int wParam, IntPtr lParam);

        public const int WM_GETTEXT = 0xD;

        private void button2_Click(object sender, EventArgs e)

        {

            if (pcalc == null || pcalc.HasExited) return;

            IntPtr hEdit = FindWindowEx(pcalc.MainWindowHandle, IntPtr.Zero, "Edit", null);

            string w = " ";

            IntPtr ptr = Marshal.StringToHGlobalAnsi(w);

            if (SendMessage(hEdit, WM_GETTEXT, 100, ptr))

            {

                MessageBox.Show(Marshal.PtrToStringAnsi(ptr));

            }

        }

    }

}

using System;

using System.Diagnostics;

using System.Runtime.InteropServices;

using System.Windows.Forms;



namespace CSharpWin02

{

    public partial class Form2 : Form

    {

        public Form2()

        {

            InitializeComponent();

        }



        Process pcalc = null;

        //启动计算器

        private void button1_Click(object sender, EventArgs e)

        {

            pcalc = Process.Start("calc.exe");

        }



        //获取文本框的结果

        [DllImport("user32.dll", EntryPoint = "FindWindow")]

        public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll", EntryPoint = "FindWindowEx")]

        public static extern IntPtr FindWindowEx(IntPtr hWnd1, IntPtr hWnd2, string lpsz1, string lpsz2);

        [DllImport("User32 ")]

        public static extern bool SendMessage(IntPtr hWnd, int Msg, int wParam, IntPtr lParam);

        public const int WM_GETTEXT = 0xD;

        [DllImport("user32.dll", EntryPoint = "SetForegroundWindow")]

        public static extern int SetForegroundWindow(IntPtr hwnd);

        private void button2_Click(object sender, EventArgs e)

        {

            if (pcalc == null || pcalc.HasExited) return;

            string result = "";//最终获得计算器的结果

            if (Environment.OSVersion.Version.Major >= 6)//win7 or vista

            {

                //vista or win7发送ctrl+c获取返回值

                SetForegroundWindow(pcalc.MainWindowHandle);

                SendKeys.Send("^(C)");

                result = Clipboard.GetText();

            }

            else

            {

                //xp或更早版本寻找对应控件获得返回值

                IntPtr hEdit = FindWindowEx(pcalc.MainWindowHandle, IntPtr.Zero, "#32770", null);

                string w = " ";

                IntPtr ptr = Marshal.StringToHGlobalAnsi(w);

                if (SendMessage(hEdit, WM_GETTEXT, 100, ptr))

                {

                    result = Marshal.PtrToStringAnsi(ptr);

                }

            }

            MessageBox.Show(result);

        }

    }

}

string result = new System.Data.DataTable().Compute("1+2+5", "").ToString();