How to keep the Text of a Read only TextBox after PostBack()?

Question

I have an ASP.NET TextBox and I want it to be ReadOnly. (The user modify it using another control)

But when there is a PostBack()

Answer 1

Another solution I found and easier one:

Add this to the Page Load method:

protected void Page_Load(object sender, EventArgs e)
{
     TextBox1.Attributes.Add("readonly", "readonly");
}