How to convert Databand as Recursive Band????

[Edward]

MyDataSource - the DataSource in the report which is contains your data.
level - it is a field in the MyDataSource which contains an integer value which sets a level of the nesting that field in your tree. So you need additional field to build the report.
Example data:
Category_id parent_category level
1 ------------------ 0 -------------------0
2 ------------------ 1 -------------------1
3 ------------------ 1 -------------------1
4 ------------------ 2 -------------------2
5 ------------------ 2 -------------------2
6 ------------------ 4 -------------------3
7 ------------------ 4 -------------------3

Thank you.