[wxhaskell-users] TreeCtrl Drag and Drop

[<wxh...@al...>]

Hello again,

Continuing with my last example, I have been trying to get drag and drop
working for trees.  Is this implemented yet?  The following doesn't seem
to work with or without the "veto" line commented out.  Any guidance
would be appreciated.  If it hasn't been implemented yet, how much work
would be required to do so?

Thanks

module Main where
 
import Graphics.UI.WX
import Graphics.UI.WXCore
 
imageNone :: Int
imageNone = (-1)
 
appendChild tree parent child = treeCtrlAppendItem tree parent child
imageNone imageNone objectNull
 
appendList tree parent children = mapM_ (appendChild tree parent)
children
 
main :: IO()
main = start test
 
test :: IO()
test = do f <- frame [text := "Hello!"]
          tree <- treeCtrl f []
          root <- treeCtrlAddRoot tree "Root" imageNone imageNone
          objectNull
          child1 <- treeCtrlAppendItem tree root "Child1" imageNone
          imageNone objectNull
          child2 <- treeCtrlAppendItem tree root "Child2" imageNone
          imageNone objectNull
          appendList tree child1 ["A","B","C"]
          appendList tree child2 ["1","2","3"]
          set tree [on treeEvent := onTreeEvent tree]
          set f [layout := fill $ widget tree, clientSize := sz 500 300]
 
 
onTreeEvent :: TreeCtrl a -> EventTree -> IO ()
onTreeEvent t event
  = case event of
      TreeBeginDrag item point veto
        -> do putStrLn "started dragging..."
              veto
              propagateEvent
      TreeEndDrag item point
        -> do putStrLn "stopped dragging..."
              propagateEvent
      other
        -> propagateEvent