Pass an argument to a function in R environment, (gWidget)

Question

I have a list of data table of :

PID_short   PID_full
   420      44101445
   419      44101375
   418      44101344
   417      44100125
   ...        ...
    3       44054648
    2       68049258
    1       68051786

And here is my code :

require(gWidgets)

w <- gwindow("bigfoot") 
g <- ggroup(cont = w, horizontal = FALSE) 
g1 <- ggroup(cont = w) 
g2 <- ggroup(cont = w)
Vl <- list () 

fr3 <- gframe ("", cont=g, horizontal=TRUE) 
l3 <- glayout ( cont = fr3 , expand=TRUE) 
l3 [1,1] <- NbS <- glabel("PID_short", cont = l3) 
l3 [1,2] <- (Vl$NbS <- gcombobox ((c(1:420)), cont = l3)) 

ok <- gbutton("OK", cont = g, handler=rbC) 

fr4 <- gframe ("", cont=g, horizontal=FALSE) 
l4 <- glayout (cont=fr4, expand = TRUE) 
l4 [1,1] <- Dm <- glabel("PID_full", cont = l4) 
l4 [1,2] <- (Vl$Dm <- gedit("", cont = l4))

Okay, I wish that when I select 420 in the gcombobox and press ok, the PID_full will tell me 44101445, like in the table, and so on.

But I don't know how to pass an argument to a function as I am actually new to R. Can anyone help me? I hope I provided a clear information...if anything unclear, I will update it, thanks a lot, will appreciate it.