using System;
using System.Windows.Forms;
public class Form1 : Form
{
private TextBox textBox1;
private Button button1;
public Form1()
{
textBox1 = new TextBox();
button1 = new Button();
button1.Text = "Submit";
button1.Click += new EventHandler(button1_Click);
textBox1.TextChanged += new EventHandler(textBox1_TextChanged);
this.Controls.Add(textBox1);
this.Controls.Add(button1);
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
if (textBox1.Text.Length > 10)
{
textBox1.BackColor = Color.Red;
}
else
{
textBox1.BackColor = Color.White;
}
}
private void button1_Click(object sender, EventArgs e)
{
if (textBox1.Text.Length > 10)
{
MessageBox.Show("Text is too long!");
}
else
{
MessageBox.Show("Text is valid!");
}
}
[STAThread]
public static void Main()
{
Application.Run(new Form1());
}
}