import sys
from PyQt5.QtGui import *
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import Qt

class Combo(QComboBox):
    def __init__(self, title, parent):
        super(Combo, self).__init__(parent)
        self.setAcceptDrops(True)
    
    def dragEnterEvent(self, e):
        print(e)
        if e.mimeData().hasText():
            e.accept()
        else:
            e.ignore()
    
    def dropEvent(self, e):
        self.addItem(e.mimeData().text())

class Example(QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.initUI()
    
    def initUI(self):
        lo = QFormLayout()
        lo.addRow(QLabel("請把左邊的文本拖拽到右邊的下拉菜單中"))
        edit = QLineEdit()
        edit.setDragEnabled(True)
        com = Combo("Button", self)
        lo.addRow(edit, com)
        self.setLayout(lo)
        self.setWindowTitle("簡單的拖拽例子")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    win = Example()
    win.show()
    sys.exit(app.exec_())

import os
import sys
from PyQt5.QtCore import QMimeData
from PyQt5.QtWidgets import (QApplication, QDialog, QGridLayout, QLabel, QPushButton)
from PyQt5.QtGui import QPixmap

class Form(QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)
        textCopyButton = QPushButton("&Copy Text")
        textPasteButton = QPushButton("Paste &Text")
        htmlCopyButton = QPushButton("C&opy HTML")
        htmlPasteButton = QPushButton("Paste &HTML")
        imageCopyButton = QPushButton("Co&py Image")
        imagePasteButton = QPushButton("Paste &Image")

        self.textLabel = QLabel("Original text")
        self.imageLabel = QLabel()
        self.imageLabel.setPixmap(QPixmap(os.path.join(os.path.dirname(__file__), "images/clock.png")))

        layout = QGridLayout()
        layout.addWidget(textCopyButton, 0, 0)
        layout.addWidget(imageCopyButton, 0, 1)
        layout.addWidget(htmlCopyButton, 0, 2)

        layout.addWidget(textPasteButton, 1, 0)
        layout.addWidget(imagePasteButton, 1, 1)
        layout.addWidget(htmlPasteButton, 1, 2)

        layout.addWidget(self.textLabel, 2, 0, 1, 2)
        layout.addWidget(self.imageLabel, 2, 2)
        self.setLayout(layout)

        textCopyButton.clicked.connect(self.copyText)
        textPasteButton.clicked.connect(self.pasteText)
        imageCopyButton.clicked.connect(self.copyImage)
        imagePasteButton.clicked.connect(self.pasteImage)
        htmlCopyButton.clicked.connect(self.copyHtml)
        htmlPasteButton.clicked.connect(self.pasteHtml)

    def copyText(self):
        print(os.path.join(os.path.dirname(__file__)))
        clipboard = QApplication.clipboard()
        clipboard.setText("I've been clipped")

    def pasteText(self):
        clipboard = QApplication.clipboard()
        self.textLabel.setText(clipboard.text())
    
    def copyImage(self):
        clipboard = QApplication.clipboard()
        clipboard.setPixmap(QPixmap(os.path.join(os.path.dirname(__file__), "images/python.jpg")))

    def pasteImage(self):
        clipboard = QApplication.clipboard()
        self.imageLabel.setPixmap(clipboard.pixmap())
    
    def copyHtml(self):
        mimeData = QMimeData()
        mimeData.setHtml("<b>Bold and<font color=red>Red</font></b>")
        clipboard = QApplication.clipboard()
        clipboard.setMimeData(mimeData)

    def pasteHtml(self):
        clipboard = QApplication.clipboard()
        mimeData = clipboard.mimeData()
        if mimeData.hasHtml():
            self.textLabel.setText(mimeData.html())

            
if __name__ == "__main__":
    app = QApplication(sys.argv)
    win = Form()
    win.show()
    sys.exit(app.exec_())