Get Set values of TextBox Control from server side

Question

Let say I have this code on Page load of ASP.NET Webform

protected void Page_Load(object sender, EventArgs e)
{
    TextBox1.Text = "123";
}

and this is my control in aspx file

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />

If I change the textbox data from 123 to 12548 or any thing in the front end and then I click the button Now in this is my code behind button click event

protected void Button1_Click(object sender, EventArgs e)
{
    string s = TextBox1.Text;
}

Now in TextBox1.Text I should be getting 12548 or updated value instead I am getting 123 which I have already set in page load.

Now I want to get the updated value, how may I do it the right way.

Answer 1

Wrap it in a NOT is Postback

  protected void Page_Load(object sender, EventArgs e)
{ 
 if(!IsPostBack)
    {
      TextBox1.Text = "123";
    }
}

or remove it completely:

protected void Page_Load(object sender, EventArgs e)
{
  //not here
}

<asp:TextBox ID="TextBox1" Text="123" runat="server"></asp:TextBox>