protected void ddlSubject_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (ddlSubject.SelectedIndex != 0)
        {
            if (SubjectModel.subjectType(ddlSubject.SelectedValue) == "L")
            {
                rdbL.Enabled = true;
                rdbT.Enabled = true;
            }
            else
            {
                rdbSubjectType.SelectedIndex = 0;
                rdbL.Enabled = false;
                rdbT.Enabled = false;
            }

            ArrayList auxPA = DbConnection.getDbData("SELECT SUM(percentage) FROM Activity WHERE idSubject = '" + ddlSubject.SelectedValue + "' AND idType = '" + rdbSubjectType.SelectedValue + "';");
            double    auxP  = 0;
            double.TryParse((String)auxPA[0], out auxP);
            lblPercentage.Text = "Porcentaje de la actividad [Disponible: " + (100 - (auxP * 100)) + "%].";
        }
        else
        {
            rdbSubjectType.SelectedIndex = 0;
            rdbL.Enabled = false;
            rdbT.Enabled = false;
        }
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        if ((!IsPostBack))
        {
            rdbSubjectType.SelectedIndex = 0;
            rdbL.Enabled = false;
            rdbT.Enabled = false;

            if (Request.QueryString["idSubject"] != null)
            {
                if (SubjectModel.subjectType(Request.QueryString["idSubject"]) == "L")
                {
                    ddlSubject.SelectedValue = Request.QueryString["idSubject"];
                    rdbL.Enabled             = true;
                    rdbT.Enabled             = true;
                }
            }
        }
    }