This study is focused on the relationships among learning styles, participation types, and learning performance for programming language learning supported by an online forum. Kolb's learning style inventory was used in this study to determine a learner's learning type: "Diverger", "Assimilator", "Converger", and "Accommodator". Social Learning Theory was also used to define four participation types. These types in turn were used to describe the learning associated with the use of online forums: "Replier", "Asker", "Watcher", and "No activity". A total of 144 students participated in this experiment as part of a half semester ASP.NET programming language learning courses. The course contained an online forum for supporting the students' social activities and participation. In this study, "learning score" and "satisfaction" were used to measure learning performance. The results of this study were the following: (1) different learning styles were associated with significantly different learning scores and that the "Accommodator" style was associated with superior learning scores; (2) participation types were also associated with significantly different learning scores and that the "Replier" type is associated with superior learning scores; (3) learning satisfaction is not significantly different among the different learning styles or different participation types, but the average is significantly higher than average values (3.5) of 7-point Likert scale; (4) there is no significant association between learning styles and participation types. Explanations and discussions of these results are offered. Based on the results of this study, we propose that programming language learning, supported with online forums and students' active participation, increases learning performance as measured by student learning scores. (Contains 2 figures and 2 tables.)