using System;
using System.Drawing;
using System.Windows.Forms;

class MainForm : Form
{
	Button btn;
	MainForm() {
		Text = "Main window";
		ClientSize = new Size(400, 300);
		btn = new Button();
		btn.Size = new Size(200, 50);
		btn.Text = "Show sub window.";
		Controls.Add(btn);
		btn.Click += btn_Click; 
	}
	void btn_Click(object sender, System.EventArgs e) {
		ShowSubFormWithText("this is a sample."); 
	}
	static void ShowSubFormWithText(string text) {
		SubForm f = new SubForm(text);
		f.ShowDialog();
	}
	[STAThread]
	static void Main(string[] args) {
		Application.Run(new MainForm());
	}
}
class SubForm : Form
{
	TextBox txt;
	public SubForm(string text) {
		Text = "Sub window";
		ClientSize = new Size(300, 150);
		StartPosition = FormStartPosition.CenterParent;
		txt = new TextBox();
		txt.Text = text;
		txt.Multiline = true;
		txt.ScrollBars = ScrollBars.Both;
		txt.Dock = DockStyle.Fill;
		txt.KeyDown += txt_KeyDown;
		Controls.Add(txt);
	}
	void txt_KeyDown(object sender, KeyEventArgs e) {
		if (e.Control && e.KeyCode == Keys.A) 
		{ 
			txt.SelectAll(); 
		}
	}
}