The words in the chart legend is too long and legend size is small so users cann't see the whole words, how to make the words automatically displayed to the next line? By the way, I don't want to change the legend size because it's big though.
Sorry, the legend does not wrap its text automatically. However, you can do this manually by implementing IRenderLabel interface. In its ToString method you can insert line breaks to move parts of the text to the new line. There is a knowledge base article with a similar implementation of IRenderLabel (you would just insert line breaks instead of trimming the text):http://devcenter.infragistics.com/Support/KnowledgeBaseArticle.aspx?ArticleID=9997
You can submit this as a feature request through the support group if you would like to see this implemented in the future:http://es.infragistics.com/gethelp