hi Andreas,
You can access to each element of the collection like this:
Create your column
For a table:
CREATE TABLE `test` (
`i` int(11) NOT NULL AUTO_INCREMENT,
`colgeo` geometry DEFAULT NULL,
`collectingdata` geometrycollection DEFAULT NULL,
PRIMARY KEY (`i`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1;
insert some data
INSERT INTO test values(3 ,ST_geomfromtext('POINT(47.37 -122.21)'), st_geomfromtext('GeometryCollection(Point(1 1), LineString(2 2, 3 3))'));
// number 2 is the index of the element
SELECT AsText(GeometryN(collectingdata, 2)) FROM test;
These statements can be send and read using MySQLCommand and MySqlDataReader
Please give it a try and let us know if this worked for you.
Here is a blog post about MySqlGeometry, although it is not on collections but I think it could help.
https://blogs.oracle.com/MySqlOnWindows/entry/howto_storing_and_retrieving_spatial
Thanks,