using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsPopupKeyboard
{
    public partial class Form1 : Form
    {
        Keyboard keyboard;
        public Form1()
        {
            InitializeComponent();
        }

        /******************************************
         *  I had to hook up the textBox_GotFocus event handler method manuall in the Form's 
         *  Designer.cs file using:
         * 
         *  this.textBox1.GotFocus += new System.EventHandler(this.textBox_GotFocus);
         * 
         *****************************************/
        private void textBox_GotFocus(Object sender, EventArgs e)
        {
            TextBox tb = (TextBox)sender;  // take a copy of the object reference for the particular textbox pressed

            label1.Text = "TextBox " + tb.Name  + " GotFocus " + DateTime.Now.ToString();  // just some debugging to see which textbox has focus

            if (keyboard == null)  // check if the keyboard is already created
            {
                keyboard = new Keyboard();   // no keyboard so create an instance of one
                keyboard.FormClosed += delegate 
                  {
                      keyboard = null;  // when the keyboard is closed, dispose of the keyboard instance
                      this.ActiveControl = label1; // when the keyboard is closed, reset focus to the dummy label else
                                                   // it will give focus to a textbox which would trigger the event to
                                                   // make another keyboard appear.
                  };
            }
            keyboard.setTextBoxForOutput(tb);  // tell the keyboard which textbox to send its characters too
            keyboard.Show(); // show the keyboard

            keyboard.Left = this.Left + tb.Left + tb.Width + 30;  // re-position the keyboard form to be next to
            keyboard.Top = this.Top + tb.Top + tb.Height + 11;    // the textbox that recieves its input.
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.ActiveControl = label1;    // when the form loads, direct focus to a label so that a textbox 
                                            // doesn't get focus by default and trigger the GotFocus event (which
                                            // would show the keyboard before we needed it)
        }
    }
}