Transfer Value from .aspx.cs to .aspx

Question

Consider a sample Page 

Page1.aspx.cs and Page1.aspx

In Page.aspx.cs :  string name1 = "License";

In Page1.aspx: <ap:textbox id="id1" runat="server" Text = ? >

How to display the name from .aspx.cs to .aspx?

i.e.   name1 must be in id1 textbox.