cant get personalization working

[johnyperu]

hi,

Can anyone please help me out on this.
I just want to get something very basic going but cant see my mistake and
dont know if i am missing this concept.

I just want to allow a user to enter their post code and then for
it to be rendered next time.

I have a text box that shows the users zip
under that there is a label 'enter your new zip'
a submit button and another text box so a user can enter\edit
their zip.
This should be so easy !!

But each time i submit the page the value is lost.
I dont think WebBrowsable is needed as its nothing to do with this.

ps: i hate posting code and never normally do it !!

=====

namespace zip
{
[Guid("cab4158f-bfe0-484d-b6a8-04ad1dff5a14")]
public class zip : System.Web.UI.WebControls.WebParts.WebPart
{
public zip()
{
this.ExportMode = WebPartExportMode.All;
}

private string _myZip = "";
private TextBox tmyZIP;
private Button btnSubmit;
private Label lblSubmit;
private TextBox tDataNewZIP;

[Personalizable()]
public string myZip
{
get { return _myZip; }

set { _myZip = value; }
}

protected override void OnLoad(EventArgs e)
{
if (myZip.Length > 0)
{
this.tmyZIP.Text = myZip;
}
}





protected override void CreateChildControls()
{
tmyZIP = new TextBox();
tmyZIP.ID = "tmyZIP";
tmyZIP.Text = "";
Controls.Add(tmyZIP);

lblSubmit = new Label();
lblSubmit.ID = "lblSubmit";
lblSubmit.Text = "enter a new zip here";
Controls.Add(lblSubmit);

btnSubmit = new Button();
btnSubmit.ID = "btnSubmit";
btnSubmit.Text = "Submit";
btnSubmit.Click += new EventHandler(this.btnSubmit_Click);
Controls.Add(btnSubmit);

tDataNewZIP = new TextBox();
tDataNewZIP.ID = "tDataNewZIP";
tDataNewZIP.Text = "";
Controls.Add(tDataNewZIP);
}

private void btnSubmit_Click(object sender, EventArgs e)
{
if (tDataNewZIP.Text.Length > 0)
{
myZip = tDataNewZIP.Text.ToString();
tmyZIP.Text = tDataNewZIP.Text.ToString();
}
}


protected override void Render(HtmlTextWriter writer)
{
EnsureChildControls();

writer.Write("<br/> this is your post code");
this.tmyZIP.RenderControl(writer);

writer.Write("<br/><br/>");
lblSubmit.RenderControl(writer);
btnSubmit.RenderControl(writer);
tDataNewZIP.RenderControl(writer);
}
}