dragDrop

Type

message

Summary

Sent to the object where data was dropped when a drag and drop finishes.

Syntax

dragDrop

Description

Handle the dragDrop message to perform an action when the user drops data, or trap the message to prevent text from being dropped.

The dragDrop message is sent to the control where data is being dragged.

Important

If the acceptDrop property is set to false at the time the drop occurs, no dragDrop message is sent.

LiveCode automatically handles the mechanics of dragging and dropping text between and within unlocked fields. To support this type of drag and drop operation, you don't need to do any scripting: the text is dropped into the field automatically when LiveCode receives the dragDrop message.

To prevent an unlocked field from accepting a drag and drop, trap the dragDrop message. If you don't want to allow a particular field to accept text drops, place a dragDrop handler in the field that does not contain a pass control structure:

    on dragDrop -- in script of field or one of its owners
        -- do nothing, but trap the message
    end dragDrop

On the other hand, if you want to perform some action when text is dropped into an unlocked field, you need to pass the dragDrop message once you're done with it in order to allow the drop to take place:

    on dragDrop
        set the cursor to 9023
        pass dragDrop -- needed for drop to occur
    end dragDrop

To accept drops to a locked field or a control other than a field, handle the dragDrop message, using the dragData property to determine what data is being dragged. For these objects, your dragDrop handler must get the dragged data and put it into the object (or perform whatever action you want to do on a drop); the behavior is not automated as it is for unlocked fields.

Examples

on dragDrop -- check whether a file is being dropped
  if the dragData["files"] is empty then beep 2
  pass dragDrop
end dragDrop

Related

control structure: pass

function: dropChunk, dragSource

glossary: object, property, handler, message, unlock, control structure, drag and drop, control, trap

keyword: field

message: dragEnd

object: field

property: dragData, acceptDrop, dragImageOffset, dragAction

Compatibility and Support

Introduced

LiveCode 2.0

OS

mac

windows

linux

Platforms

desktop

server