i have object from class like this :

class student

{

private int st_ID;

private string name ;

private material[ mt;

}

class material

{ 

private int st_ID;

private int mt_ID;

private string name ;

private mark[ mk;

}

class mark

{

private int mk_ID;

private int mt_ID;

private string name ;

}

now i recive object from student like this :

student [ ] std  = new student[ ] { };

what i need to disblay in tree :

1- in first level the student name

2-in second  level the material

3 in thired level the mark

remark : may be the student have mark may be not and may be have material and my be not