To insert item into 2 combo boxes & also to print the output in the text area provided

Question

Here i am having 2 combo boxes in which one holds devices & other holds operations.these 2 combo boxes should interact in such a way that the device selected in box1 should list out the operations performed in box2 & simultaneously it should print the equivalent code in the text area from the text file present in the project & at the end if the user needs to change the code printed the text area & also the changed code must be saved in the same text file on clicking the save button located below it.

I need the solution as soon as possible