lost dynamically created text box values

See more:

C#

ASP.NET

Hi all,
Please see below code:

        protected void btnAddField_click( Object sender, EventArgs e ) {
        int FieldCount = 0;
        if (ViewState["FieldCount"] != null)
        {
            FieldCount = (int)ViewState["FieldCount"];
        }
        
        Table tbl = new Table();
        if (Session["DynamicTable"] != null)
        {
            tbl = (Table)Session["DynamicTable"];
        }
 
        CheckBox chkNewField = new CheckBox();
        chkNewField.ID = "chkNewField" + FieldCount.ToString();
        chkNewField.Checked = true;
 
        Label LblNewLabel = new Label();
        LblNewLabel.ID = "lblNewLabel" + FieldCount.ToString();
        LblNewLabel.Text = "New Lable";
 
        TextBox TxtNewLabel = new TextBox();
        TxtNewLabel.ID = "TxtNewLabel" + FieldCount.ToString();
 
        Label LblNewValue = new Label();
        LblNewValue.ID = "lblNewValue" + FieldCount.ToString();
        LblNewValue.Text = "New Value";
 
        TextBox TxtNewValue = new TextBox();
        TxtNewValue.ID = "TxtNewValue" + FieldCount.ToString();
 
        TableRow tRow = new TableRow();
 
        TableCell tCell1 = new TableCell();
        TableCell tCell2 = new TableCell();
        tCell2.Attributes.Add("class", "medium");
        TableCell tCell3 = new TableCell();
        tCell3.Attributes.Add("class", "medium");
        TableCell tCell4 = new TableCell();
        TableCell tCell5 = new TableCell();
        tCell5.Attributes.Add("class", "medium");
        TableCell tCell6 = new TableCell();
        tCell6.Attributes.Add("class", "medium");
 
        tCell1.Controls.Add(chkNewField);
        tCell2.Controls.Add(LblNewLabel);
        tCell3.Controls.Add(TxtNewLabel);
        tCell4.Controls.Add(new LiteralControl(""));
        tCell5.Controls.Add(LblNewValue);
        tCell6.Controls.Add(TxtNewValue);
 
        tRow.Cells.Add(tCell1);
        tRow.Cells.Add(tCell2);
        tRow.Cells.Add(tCell3);
        tRow.Cells.Add(tCell4);
        tRow.Cells.Add(tCell5);
        tRow.Cells.Add(tCell6);
 
        tbl.Rows.Add(tRow);
        placeHolderTable.Controls.Remove(tbl);
        placeHolderTable.Controls.Add(tbl);
        Session["DynamicTable"] = tbl;
        FieldCount++;
        ViewState["FieldCount"] = FieldCount;
}

Dynamically adding fields are working fine. But

1. the values i entered in text boxes clearing on each post back
2. I failed to fetch values from text boxes.

protected void BtnPublish_click( object sender, EventArgs e ) { TextBox tb = (TextBox)placeHolderTable .FindControl( "TxtNewLabel1" ); }

This code not working.
Please help me.
Thanks in advance,
Manu