How I can develop a dynamic roster questions in web limesurvey service?

I'm not familiar with dynamic roster questions. You might explain it a bit more to maximize chances of getting an answer. What version of LimeSurvey do you use?

Never heard of a "dynamic roster question" before, but seems like a array/matrix type question with text boxes, or even with different question types per column. This could be done via Workarounds in LS, there is no out of the box feature for this.

The dynamic part is probably the loop feature you are missing so much in LS.
This is also only available as a workaround and I am not sure if it will work in combination with the above workaround, as you would actually have to apply it to several questions at the same time.

If you would give a more concrete example (what question types each column would have), then maybe Tpartner can tell you if it is possible.

And for using the workarounds it is important to know your Limesurvey version, because different approaches might apply.

A dynamic roster questions is like a Field Collection. It allows a set of fields to be combined together and treated as a single field. For example, a field collection named Playlist can be created consisting of the text fields Song and Artist. When a Playlist entry is created the Song and Artist fields are presented together as elements of the Playlist field. But it is dynamic, because before somebody insert it we don't know how many Playlist we have. It's a user desition. The user can insert unlimited Playlist. It´s for me dynamic.

OK, so it is basically what i thought.

Both things separately can be achieved via workarounds. The tricky part will be to make those two workarounds work together. I guess only Tpartner can really answer this question.

Which is why I asked what question types you would like to be used per column? If it is only text, then you can use a matrix/array question with text fields ( www.limesurvey.org/manual/Question_types#Array_.28Texts.29 ).

In this case I am sure the workaround for hiding subquestions (lines) can be used. However, it is not 100% dynamic. You still need to create a certain amount of subquestions and then hide them. This only works if you have a maximum number of responses.
Here the workaround: www.limesurvey.org/manual/Workarounds:_M...ipt#Expandable_Array (might not work for your version of LS, but you haven't told us your version, so we can't tell).

E.g. if you are asking for the members of a family, I guess you are save when you stop at about 20. With your example of a play list this can get a lot trickier, because in theory there can be a very, very long list.

However, you might run into another problem if you have a big number of possible entries. This limit is imposed by the MySQL database engine: you can create about 1000 columns. If you use an array question text, you can reach this limit quite quickly. Lets assume you have 10 columns to fill, than you might already reach the database limit with just this question, if you allow 100 or more entries. (10x100=1000).