Best way to display list content coming from different site collections in a webpart?

I would like to build a webpart that is going to display list content coming from different site collections (but the same content type).

I wanted to use the SPSiteDataGuery to create the开发者_StackOverflow中文版 datasource of a SPGridView for instance, but it appears to be working only within the same site collection. Do you have any idea ?

The best performing solution would be to use the search object model. Look into FullTextSqlQuery. You can filter based on content type easily enough. The downside in using this technique is obviously there is a delay until the content is crawled. The performance over anything else however will be significantly better. Waldek has some great articles on comparing the alternatives.