I need to dynamically add/remove dimensions and facts in web application and get results from SSAS. The cube in SSAS is defined and ready to use. So far the best idea I found is use MDX queries to get metadata from SSAS cube and display those data in web page. Then user can choose needed dimensions/facts and I need to costruct dynamic MDX query and get results from SSAS. Communication with SSAS is made with AdomdDataReader. Is there better options to solve this task that require less effor? Maybe somehow make use of Reporting Services (SSRS).
Do you mean you have to dynamically modify the cube structure? If so, that can be done via AMO: http://msdn.microsoft.com/en-us/library/ms345093.aspx
If you need to build a GUI for MDX queries, check out this: http://ranetuilibraryolap.codeplex.com/
Its not specifically for ASP.NET (Silverlight is supported though), perhaps you can reuse some of the code.