Text disappears on page load

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ASP.NET

Hello to all,
I have an asp.net web application.In that i have a form,In the form I have

1.) 4 Text box
2.) two combo box
3.) Four buttons


I entered the text in first text box and select the item from those two combobox. Now there is another textbox and a

button named as add in front of it. When clicks on add after entering the text in that text box, the whole entry from the

form disaapears. Actually I have a main button names as save..I wants to save all the information but before that page

loads and all the information become disappears.

How could i hold the text when page load..I am struggling from last 16 days,yet not get the solution...
This is my page load and all Enableviewstate is true for all controls

protected void Page_Load(object sender, EventArgs e)
{
//page load
if (!Page.IsPostBack)
{
//if (Request.QueryString["id"] != null)
//{

//}
//else if (Request.QueryString["id"] == null)
//{
//btnSubmitAll.Visible = true;
//laberror.Visible = false;
//btnUpdate.Visible = false;
//btnUpdatePro.Visible = false;
//btnUpdateRef.Visible = false;
//btnUpdateStatus.Visible = false;

ds1 = con.ExecuteSPDS("TypeOfDll", "0", "ddlDailyReport");
if (ds1.Tables.Count > 0)
{
if (ds1.Tables[1].Rows.Count > 0)
{
ddlProduct.DataSource = ds1.Tables[1];
ddlProduct.DataTextField = "ProductName";
ddlProduct.DataValueField = "Id";
ddlProduct.DataBind();
ddlProduct.SelectedValue = "0";
}

if (ds1.Tables[0].Rows.Count > 0)
{
ddlHOffState.DataSource = ds1.Tables[0];
ddlHOffState.DataTextField = "State";
ddlHOffState.DataValueField = "Id";
ddlHOffState.DataBind();
ddlHOffState.SelectedValue = "0";
}

if (ds1.Tables[2].Rows.Count > 0)
{
ddlref.DataSource = ds1.Tables[2];
ddlref.DataTextField = "Reference";
ddlref.DataValueField = "Id";
ddlref.DataBind();
ddlref.SelectedValue = "0";
}

if (ds1.Tables[3].Rows.Count > 0)
{
ddlstatus.DataSource = ds1.Tables[3];
ddlstatus.DataTextField = "SalesStatus";
ddlstatus.DataValueField = "Id";
ddlstatus.DataBind();
ddlstatus.SelectedValue = "0";
}

if (ds1.Tables[4].Rows.Count > 0)
{
ddlOffType.DataSource = ds1.Tables[4];
ddlOffType.DataTextField = "OffType";
ddlOffType.DataValueField = "Id";
ddlOffType.DataBind();
ddlOffType.SelectedValue = "0";
}
//}

//fill ds for grids//
}

}
if (Request.QueryString["id"] != null)
{
Filleditgrid();
}
else if (Request.QueryString["id"] == null)
{
FillDs();
}


// btnUpdOffContact.Visible = false;

}

[Edit]code block moved from answer[/Edit]
Plz help me