Compare two datatables

i have two datatables with only one column each. i wanted to compare those two columns in two datatables. here is the example.. i am using C#.Net a开发者_如何转开发nd WPF for achieving this.

dt1 
apple
orange
peach
banana

dt2
apple
peach
mango
apricot

now i want to compare dt2 with dt1. dt2 is bound to a list box. so once i match with dt1, the unmatched items selection should be diabled. here i wanted the mango and apricot selection to be disabled..

hope i am clear..

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Populate the list box with items from dt2, but enable only the items returned by dt1 join dt2 on dt1.column_name = dt2.column_name.