<br />
TextBox2.Enabled=false;<br />
TextBox3.Enabled=false;<br />
<br />
<br />
<br />
TextBox1.TextChanged += new EventHandler(TextBox1_TextChanged);<br />
<br />
void TextBox1_TextChanged(object sender, EventArgs e<br />
{<br />
TextBox2.Enabled=true;<br />
}<br />
<br />
void TextBox2_TextChanged(object sender, EventArgs e)<br />
{<br />
TextBox3.Enabled=true;<br />
}