MS Word's Add-in TextChange Event in C#

Question

I have a Microsoft Word Add-in that find the similar words in a text (But When I click a button !)

My question is : how to call a function when user typed words ?

In other word , i want an event like "TextChange" or "Keypress" when user typing to get the current word and process it and get it's similar words.

Somethings Like this :

private void TextChangeEventOfCurrentActiveDocument(object sender, System.EventArgs e)
{
    ...
}

Any Other idea that i can get new words that user typed ?

Thanks.

Answer 1

Finally after a long time, i create this add-in by using Windows hooks.

(Special thanks to @Reg Edit)

Here the entire code that i wrote and this work nice for me. (some optional section of code was removed.)

ThisAddIn.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Word = Microsoft.Office.Interop.Word;
using Office = Microsoft.Office.Core;
using Microsoft.Office.Tools.Word;
using System.Windows.Forms;

using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;

namespace PersianWords
{
    public partial class ThisAddIn
    {

        private const int WH_KEYBOARD_LL = 13;
        private const int WM_KEYDOWN = 0x0100;

        private static IntPtr hookId = IntPtr.Zero;
        private delegate IntPtr HookProcedure(int nCode, IntPtr wParam, IntPtr lParam);
        private static HookProcedure procedure = HookCallback;

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook, HookProcedure lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

        private static IntPtr SetHook(HookProcedure procedure)
        {
            using (Process process = Process.GetCurrentProcess())
            using (ProcessModule module = process.MainModule)
                return SetWindowsHookEx(WH_KEYBOARD_LL, procedure, GetModuleHandle(module.ModuleName), 0);
        }


        private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
        {

            if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
            {
                int pointerCode = Marshal.ReadInt32(lParam);

                if (pointerCode == 162 || pointerCode == 160)
                {
                    return CallNextHookEx(hookId, nCode, wParam, lParam);
                }

                string pressedKey = ((Keys)pointerCode).ToString();

                //Do some sort of processing on key press
                var thread = new Thread(() =>
                {

                    MyClass.WrdApp.CustomizationContext = MyClass.WrdApp.ActiveDocument;

                    //do something with current document


                });
                thread.Start();
            }



            return CallNextHookEx(hookId, nCode, wParam, lParam);
        }


        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            hookId = SetHook(procedure);

            MyClass.WrdApp = Application;

            MyClass.WrdApp.CustomizationContext = MyClass.WrdApp.ActiveDocument;

        }


        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
            UnhookWindowsHookEx(hookId);
        }

    #region VSTO generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InternalStartup()
    {
        this.Startup += new System.EventHandler(ThisAddIn_Startup);
        this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);


    }

    #endregion
    }
}