PySimpleGUI中如何获取ListBox选中项在values列表的索引？

当ListBox中存在__str__输出相同的Event实例时，通过遍历列表或index()方法获取索引会失效——因为Pydantic模型默认按值比较，会匹配到第一个值相等的实例，而非实际选中的实例。以下是两种可行的解决方案：

方案1：直接访问底层tkinter组件获取选中索引 #

PySimpleGUI的ListBox封装了tkinter的Listbox控件，可直接调用底层方法获取选中项的索引：

修改后的完整代码：

from pydantic import BaseModel
from datetime import datetime
import PySimpleGUI as sg


class Event(BaseModel):
    title: str
    moment: datetime
    description: str

    def __str__(self):
        return f"{self.title} at {str(self.moment)}"


events_list = [
    Event(title="test", moment=datetime(2023, 7, 2), description="hi"),
    Event(title="eger", moment=datetime(2023, 7, 4), description="34twerg"),
    # 添加测试用的重复内容实例
    Event(title="test", moment=datetime(2023, 7, 2), description="another test"),
]


event_select_tab = [
    [sg.Text("event list editor")],
    [sg.Listbox(events_list, enable_events=True, key="-SELECT EVENT-", size=(25, 10))],
    [sg.Button("edit event", key="-EDIT EVENT-", enable_events=True)],
]

layout = [[sg.TabGroup([[sg.Tab("events", event_select_tab)]])]]

window = sg.Window("editor", layout)

while True:
    event, values = window.read()
    if event == sg.WIN_CLOSED:
        break
    # 处理选中事件或编辑按钮点击
    if event in ("-SELECT EVENT-", "-EDIT EVENT-"):
        selected_items = values["-SELECT EVENT-"]
        if selected_items:
            selected_event = selected_items[0]
            # 获取底层tkinter Listbox控件
            listbox = window["-SELECT EVENT-"].Widget
            # 获取选中索引（curselection返回字符串元组，需转整数）
            selected_indices = listbox.curselection()
            if selected_indices:
                index = int(selected_indices[0])
                print(f"选中项索引: {index}，事件内容: {selected_event}")

window.close()

方案2：为Event类添加唯一标识字段 #

给Event类增加一个唯一的id字段，创建实例时赋值唯一值，选中后通过匹配id确定索引：

修改后的核心代码：

class Event(BaseModel):
    id: int  # 新增唯一标识字段
    title: str
    moment: datetime
    description: str

    def __str__(self):
        return f"{self.title} at {str(self.moment)}"


events_list = [
    Event(id=1, title="test", moment=datetime(2023, 7, 2), description="hi"),
    Event(id=2, title="eger", moment=datetime(2023, 7, 4), description="34twerg"),
    Event(id=3, title="test", moment=datetime(2023, 7, 2), description="another test"),
]

# 事件循环中获取索引部分
if event in ("-SELECT EVENT-", "-EDIT EVENT-"):
    selected_items = values["-SELECT EVENT-"]
    if selected_items:
        selected_event = selected_items[0]
        # 通过id匹配原列表索引
        index = next(i for i, e in enumerate(events_list) if e.id == selected_event.id)
        print(f"选中项索引: {index}，事件内容: {selected_event}")

内容的提问来源于stack exchange，提问作者ceayo