how to get invisible column value in grid view on image button click event

See more:

C#

ASP.NET

i have grid view with id=gv which binds at runtime ...
also i make first column invisible..
now on image button click i want to update data with that invisible column value..but i cant get that invisible column value...
plz give some idea where i m wrong..
here is my code on image button click event..

protected void imgbtnDelete_Click(object sender, ImageClickEventArgs e)
    {
        string strcon = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;
        SqlConnection conn = new SqlConnection(strcon);
        
        GridViewRow selectedRow = ((Control)sender).Parent.NamingContainer as GridViewRow;

        gv.SelectedIndex = selectedRow.RowIndex;
        string id = selectedRow.Cells[1].Text;
       
        string qry = "update dbo.[user] set isDeleted='false' where userId='" + ID + "'";
        SqlCommand cmd = new SqlCommand(qry, conn);
        conn.Open();
        int r = cmd.ExecuteNonQuery();
        if (r > 0)
        {
            Response.Redirect("editUser.aspx");

        }
        conn.Close();
    }