check box item with if canidation

I have A VB.net C# application, where i have a check list box where value like A,B,C,D, and one list box for name (AJay, Arun, Aman, Babu, Balkrishna, Bhomik, Chetan, charu, chinu. Durga, Damini, Dolly). i have to do- if i click on A of List check box then my list box value should be - Ayay,Arun,Aman and if i uncheck listbox A then all list box item shall be clear. If I Cleck B then listbox value shall be all name which is start from B.

if A click A and B then list box value shall be name which is start from A and B

Please Help to Solve this

i have tried if condition but problem is that

when i uncheck A check list box it is showing all name start from A but if i check on A and B then it is not showing and when i uncheck it is not removing value from the list box