Tkinter自定义Notebook事件参数传递与选中组件异常问题

问题分析与解决方案 #

问题1：无法访问event.data参数 #

• 原因：Tkinter的event_generate方法不支持直接通过data参数传递自定义数据到事件对象中，事件对象本身没有data属性，导致你无法直接获取该值。
• 解决方法：在CustomNotebook类中新增一个临时属性存储被关闭标签的信息，触发事件后在处理函数中通过event.widget读取该属性。

问题2：关闭标签后选中的组件不是被关闭的标签 #

• 原因：调用forget(index)移除标签后，ttk.Notebook会自动选中剩余标签中的一个（默认是前一个），被关闭的标签已经被移除，无法保持选中状态。如果需要明确知道哪个标签被关闭，通过存储的标签信息即可；如果需要在关闭前确保该标签处于选中状态，可以在移除操作前先执行选中。

修改后的完整代码 #

CustomNotebook类（修正笔误+新增数据存储）

import tkinter as tk
from tkinter import ttk

class CustomNotebook(ttk.Notebook):
    """A ttk Notebook with close buttons on each tab"""

    __initialized = False

    def __init__(self, *args, **kwargs):
        if not self.__initialized:
            self.__initialize_custom_style()
            self.__initialized = True  # 修正笔误：原代码多写了一个i

        kwargs["style"] = "CustomNotebook"
        ttk.Notebook.__init__(self, *args, **kwargs)

        self._active = None
        self._closed_tab_text = ""  # 新增：存储被关闭标签的文本

        self.bind("<ButtonPress-1>", self.on_close_press, True)
        self.bind("<ButtonRelease-1>", self.on_close_release)

    def on_close_press(self, event):
        """Called when the button is pressed over the close button"""

        element = self.identify(event.x, event.y)

        if "close" in element:
            index = self.index("@%d,%d" % (event.x, event.y))
            self.state(['pressed'])
            self._active = index
            return "break"

    def on_close_release(self, event):
        """Called when the button is released"""
        if not self.instate(['pressed']):
            return

        element =  self.identify(event.x, event.y)
        if "close" not in element:
            # user moved the mouse off of the close button
            return

        index = self.index("@%d,%d" % (event.x, event.y))

        if self._active == index:
            closed_tab_text = self.tab(index, 'text')
            self._closed_tab_text = closed_tab_text  # 存储被关闭标签的文本
            self.select(index)  # 可选：关闭前先选中该标签
            self.forget(index)
            self.event_generate("<<NotebookTabClosed>>")

        self.state(["!pressed"])
        self._active = None

    def __initialize_custom_style(self):
        style = ttk.Style()
        self.images = (
            tk.PhotoImage("img_close", data='''
                R0lGODlhCAAIAMIBAAAAADs7O4+Pj9nZ2Ts7Ozs7Ozs7Ozs7OyH+EUNyZWF0ZWQg
                d2l0aCBHSU1QACH5BAEKAAQALAAAAAAIAAgAAAMVGDBEA0qNJyGw7AmxmuaZhWEU
                5kEJADs=
                '''),
            tk.PhotoImage("img_closeactive", data='''
                R0lGODlhCAAIAMIEAAAAAP/SAP/bNNnZ2cbGxsbGxsbGxsbGxiH5BAEKAAQALAAA
                AAAIAAgAAAMVGDBEA0qNJyGw7AmxmuaZhWEU5kEJADs=
                '''),
            tk.PhotoImage("img_closepressed", data='''
                R0lGODlhCAAIAMIEAAAAAOUqKv9mZtnZ2Ts7Ozs7Ozs7Ozs7OyH+EUNyZWF0ZWQg
                d2l0aCBHSU1QACH5BAEKAAQALAAAAAAIAAgAAAMVGDBEA0qNJyGw7AmxmuaZhWEU
                5kEJADs=
            ''')
        )

        style.element_create("close", "image", "img_close",
                            ("active", "pressed", "!disabled", "img_closepressed"),
                            ("active", "!disabled", "img_closeactive"), border=8, sticky='')
        style.layout("CustomNotebook", [("CustomNotebook.client", {"sticky": "nswe"})])
        style.layout("CustomNotebook.Tab", [
            ("CustomNotebook.tab", {
                "sticky": "nswe",
                "children": [
                    ("CustomNotebook.padding", {
                        "side": "top",
                        "sticky": "nswe",
                        "children": [
                            ("CustomNotebook.focus", {
                                "side": "top",
                                "sticky": "nswe",
                                "children": [
                                    ("CustomNotebook.label", {"side": "left", "sticky": ''}),
                                    ("CustomNotebook.close", {"side": "left", "sticky": ''}),
                                ]
                            })
                        ]
                    })
                ]
            })
        ])

OutputNotebook类（修改事件处理逻辑）

class OutputNotebook:
    def __init__(self, master, **kwargs):
        self.master = master
        self.widget = CustomNotebook(master)
        self.widget.pack(pady=(8,0), anchor='ne', fill='both', expand=True)
        self.widget.bind("<<NotebookTabClosed>>", self.on_tab_closed)

    def add_table(self):
        title = f"Example {len(self.widget.children)}"

        new_tab = tk.Frame(self.widget)
        tk.Label(new_tab, text= 'Place Holder Label').pack(fill="both", expand=True)
        self.widget.add(new_tab, text=title)
        self.widget.select(new_tab)

    def on_tab_closed(self, event):
        # 获取被关闭标签的文本
        closed_tab_text = event.widget._closed_tab_text
        print(f"关闭的标签：{closed_tab_text}")
        # 可选：查看当前选中的标签
        current_selected_idx = self.widget.select()
        if current_selected_idx:
            current_selected_text = self.widget.tab(current_selected_idx, 'text')
            print(f"当前选中的标签：{current_selected_text}")

测试代码（无修改）

root = tk.Tk()
notebook = OutputNotebook(root)
button = tk.Button(
    root,
    text= 'Add new Table',
    command= notebook.add_table)

button.pack(fill='x', expand=True)
notebook.widget.pack()

root.mainloop()

内容的提问来源于stack exchange，提问作者Ruan Carlo Weiers Britzke