int c = cu.getIdCurso();
string cl = clas.getIdClase();
sentencia = "SELECT A.idAlumno, A.NºEnGrupo, A.Apellidos, A.Nombre, A.Grupo FROM ALUMNO A WHERE A.Grupo like '@c*' AND A.Grupo like '*@cl' ORDER BY A.Apellidos DESC";
OleDbDataAdapter query = new OleDbDataAdapter(sentencia, connection);
OleDbCommand selectCMD = new OleDbCommand(sentencia, connection);
query.SelectCommand = selectCMD;
selectCMD.Parameters.Add("@cl", OleDbType.VarChar);
selectCMD.Parameters["@cl"].Value = cl;
selectCMD.Parameters.Add("@c", OleDbType.Integer);
selectCMD.Parameters["@c"].Value = c;
DataSet ds = new DataSet();
query.Fill(ds, "ALUMNO");
return ds;