Well, the easiest solution is to restrict the number of characters that are going to be displayed on each columns. So If the value that is going to be displayed greater that the fixed size say 50, then add additional control dynamically or make visible if exist and once you do that will show the whole content as tooltip in this control.
Look the link below
http://i.imgur.com/zXaAj.png[
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Note: The more shows the whole content of the column value.