[Conroy]

pawn Code:

PlayerInventItems[MAX_PLAYERS][128]; // 128 is the maximum items, change if needed.

//When creating the dialog
for(new items; items <= 128; items++) // Again, 128 being the maximim items, change if needed.
{
    if(/*Item variable...*/ > 0) {
        //Add item name to list
        PlayerInventItems[playerid][items] = 1;
    }
}

//Once the player has selected the item...
new count;
for(new items; items <= 128) items++) // Again, 128 being the maximim items, change if needed.
{
    if(PlayerInventItems[playerid][items] > 0) count++;
    if(count == listitem) {
        // Do your code...
        break;
    }
}