python - wxPython - DropSource.SetData() 适用于字符串，但不适用于列表

Question

我想将一个列表项拖放到另一个列表中。两个列表都有两列。我通过将值从第一列拖放到另一个列表来实现它。但是将机器人值从第 0 列和第 1 列拖放到另一个列表将不起作用。

如何将 DropSource.SetData() 与列表一起使用？

这是我的代码的一部分:

def OnDragInit(self, event):
    #text = self.lst1.GetItemText(event.GetIndex(),0)   
    #tobj = wx.TextDataObject(text) #Doesnt work with a list
    # With the above two lines everything is working fine!
    # Error here
    text = []
    text.append(self.lst1.GetItemText(event.GetIndex(),0))
    text.append(self.lst1.GetItemText(event.GetIndex(),1))

    src = wx.DropSource(self.lst1)
    src.SetData(text)

    src.DoDragDrop(True)
    self.lst1.DeleteItem(event.GetIndex())

这是错误消息:

TypeError: DropSource.SetData(): argument 1 has unexpected type 'list'

Answer 1

我怀疑您正在将 wx.TextDropTarget 与 wx.TextDataObject 一起使用，并且您传递的显然是一个列表。< br/> 您需要创建自定义数据对象，然后在拖动时序列化列表并在放置时反序列化。

要序列化/反序列化列表，您可以使用 pickle 或 marshal，我相信您可以使用 json以及，但我并没有真正研究过这一点。

列表拖放的编码可能会变得相当复杂，因此我将这些代码放在一起，以便您直观地了解如何实现它。

代码已注释，因此希望您能够看到什么是什么。
它比实际情况稍微复杂一些，因为我允许从列数不等的列表中拖放。
另请注意，您可以拖放到同一列表中。

import wx
import pickle
#import marshal

class MyTarget(wx.PyDropTarget):
    def __init__(self, object):
        wx.DropTarget.__init__(self)
        self.object = object
        # specify the type of data to accept
        self.data = wx.CustomDataObject("ListCtrlItems")
        self.SetDataObject(self.data)

    # Called when OnDrop returns True.
    def OnData(self, x, y, opt):
        # Find insertion point in the target.
        index, flags = self.object.HitTest((x, y))

        if self.GetData():
            # unpickle data
            listdata = self.data.GetData()
            dropped_list = pickle.loads(listdata)
            #dropped_list = marshal.loads(listdata)

        if index == -1: # if not inserting, set index to the end of the listctrl
            index = self.object.GetItemCount()

        #Insert at drop point
        for row in dropped_list:
            self.object.InsertItem(index, row[0]) #Insert item
            cols = self.object.GetColumnCount()
            for pos in range(1,cols):
                try:
                    self.object.SetItem(index, pos, row[pos]) #Add extra columns data
                except Exception as e: # run out of columns in target
                    pass
            index +=1
        return True

class Mywin(wx.Frame):
    def __init__(self,parent,title):
        wx.Frame.__init__(self, parent, wx.ID_ANY, title,size= (600,-1))
        panel = wx.Panel(self)
        box = wx.BoxSizer(wx.HORIZONTAL)
        self.listCtrl1 = wx.ListCtrl(panel, -1, style = wx.LC_REPORT|wx.LC_HRULES)
        self.listCtrl1.InsertColumn(0, "Item0")
        self.listCtrl1.SetColumnWidth(0,100)
        self.listCtrl1.InsertColumn(1, "Item1")
        self.listCtrl1.SetColumnWidth(1,100)
        self.listCtrl2 = wx.ListCtrl(panel, -1, style = wx.LC_REPORT|wx.LC_VRULES|wx.LC_HRULES)
        self.listCtrl2.InsertColumn(0, "Item0")
        self.listCtrl2.SetColumnWidth(0,100)
        self.listCtrl2.InsertColumn(1, "Item1")
        self.listCtrl2.SetColumnWidth(0,100)
        self.listCtrl2.InsertColumn(2, "Item2")
        self.delete = wx.CheckBox(panel, wx.ID_ANY, "Delete on move")
        self.delete.SetToolTip("Delete original item when dragged & dropped")
        self.delete.SetValue(True)

        #load sample data
        data = [["abc",1],["def",2],["ghi",3]]
        for i in data:
            self.listCtrl1.Append((i))

        data = [["ABC",1,"first"],["DEF",2,"second"],["GHI",3,"third"]]
        for i in data:
            self.listCtrl2.Append((i))

        #Target Left
        tl = MyTarget(self.listCtrl1)
        self.listCtrl1.SetDropTarget(tl)

        #Target Right
        tr = MyTarget(self.listCtrl2)
        self.listCtrl2.SetDropTarget(tr)

        self.listCtrl1.Bind(wx.EVT_LIST_BEGIN_DRAG, self.OnDrag)
        self.listCtrl2.Bind(wx.EVT_LIST_BEGIN_DRAG, self.OnDrag)

        box.Add(self.listCtrl1, 0, wx.EXPAND)
        box.Add(self.listCtrl2, 0, wx.EXPAND)
        box.Add(self.delete, 0, wx.ALIGN_TOP)
        panel.SetSizer(box)
        panel.Fit()
        self.Centre()
        self.Show(True)

    def OnDrag(self, event):
        #create a data object for drag-and-drop
        object = event.GetEventObject() # listCtrl1 or listCtrl2
        list_data = []
        idx = -1
        while True: # find all the selected items and put them in a list
            idx = object.GetNextSelected(idx)
            if idx == -1:
                break
            item_data = []
            for item in range(object.GetColumnCount()): # get data from all columns
                item_data.append(object.GetItem(idx, item).GetText())
            list_data.append(item_data)

        # Pickle the items list.
        pickle_data = pickle.dumps(list_data)
        #pickle_data = marshal.dumps(list_data)
        # create custom data object
        cdataobj = wx.CustomDataObject("ListCtrlItems")
        cdataobj.SetData(pickle_data)
        # Now make a data object for the item list.
        data = wx.DataObjectComposite()
        data.Add(cdataobj)

        # Create drop source and begin drag-and-drop.
        dropSource = wx.DropSource(object)
        dropSource.SetData(data)
        result = dropSource.DoDragDrop(True)

        # delete dropped items from source list
        if self.delete.GetValue(): # Is delete checkbox ticked
            if result == wx.DragCopy: # Was the drag and drop successful
                while True:
                    #For this small sample always start at the beginning (-1)
                    idx = object.GetNextSelected(-1)
                    if idx == -1: #No more selected items
                        break
                    object.DeleteItem(idx)

demo = wx.App()
Mywin(None,'Drag & Drop ListCtrl Demo')
demo.MainLoop()

回答您关于从 DoDragDrop 返回的结果的评论:

The DragResult enumeration provides the following values:

Description Value
DragError Error prevented the D&D operation from completing.
DragNone Drag target didn’t accept the data.
DragCopy The data was successfully copied.
DragMove The data was successfully moved (MSW only).
DragLink Operation is a drag-link.
DragCancel The operation was cancelled by user (not an error).

DoDragDrop(self, flags=Drag_CopyOnly) Starts the drag-and-drop operation which will terminate when the user releases the mouse.

Call this in response to a mouse button press, for example.

Parameters: flags (int) – If wx.Drag_AllowMove is included in the flags, data may be moved and not only copied as is the case for the default wx.Drag_CopyOnly . If wx.Drag_DefaultMove is specified (which includes the previous flag), moving is not only possible but becomes the default operation. Return type: wx.DragResult Returns: The operation requested by the user, may be wx.DragCopy , wx.DragMove , wx.DragLink , wx.DragCancel or wx.DragNone if an error occurred.