Tkinter多级下拉菜单故障：选Plot和Cluster后无楼层选项

你在更新子区域菜单时，仅用tk._setit更新了sub_area_var变量，但没有绑定触发update_level_menu的逻辑。也就是说，当用户选择子区域时，只会更新下拉框显示的文本，不会调用更新楼层菜单的方法，所以楼层选项不会生成。

修改update_sub_area_menu方法中添加菜单命令的代码，用lambda同时实现变量更新和触发update_level_menu。另外注意Hotel-Ultra Luxury里的"52"应该改为"52F"，避免后续匹配错误。

import tkinter as tk

class App:
    def __init__(self, master):
        self.master = master
        self.master.geometry("300x200")
        self.master.title("Document Finder")

        # Create dropdown menus
        self.location_var = tk.StringVar()
        self.location_var.set("Select the Plot")
        self.location_dropdown = tk.OptionMenu(self.master, self.location_var, "Plot A", "Plot B",command = self.update_sub_area_menu)
        self.location_dropdown.pack()
        
        self.sub_area_var = tk.StringVar()
        self.sub_area_var.set("Select the sub-area")
        self.sub_area_dropdown = tk.OptionMenu(self.master, self.sub_area_var,"",command = self.update_level_menu)
        self.sub_area_dropdown.pack()

        self.level_var = tk.StringVar()
        self.level_var.set("Select a level")
        self.level_dropdown = tk.OptionMenu(self.master, self.level_var,"",command=self.update_room_menu)
        self.level_dropdown.pack()

        self.room_var = tk.StringVar()
        self.room_var.set("Select a room")
        self.room_dropdown = tk.OptionMenu(self.master, self.room_var,"")
        self.room_dropdown.pack()

        # Create button to search for document
        self.search_button = tk.Button(self.master, text="Submit")
        self.search_button.pack()

    def update_sub_area_menu(self,selection):
        if selection == "Plot A":
            sub_areas = ["Basement A", "Club Lounge", "Hotel-Luxury", "Hotel-Service Apartments", "Hotel-Ultra Luxury", "Link Levels", "Others", "Penthouses", "Podium A", "Rental Offices", "Restaurants", "Spa/Gym"]
        elif selection == "Plot B":
            sub_areas = ["Apartments-Duplex", "Apartments-Simplex", "Basement B", "Link", "Mech & Roof", "Podium B"]
        else:
            sub_areas = []
        self.sub_area_var.set("Select the sub-area")
        self.sub_area_dropdown['menu'].delete(0, 'end')
        for sub_area in sub_areas:
            # 修改这里，用lambda同时更新变量并触发update_level_menu
            self.sub_area_dropdown['menu'].add_command(
                label=sub_area,
                command=lambda sa=sub_area: [self.sub_area_var.set(sa), self.update_level_menu(sa)]
            )
    
    def update_level_menu(self, selection):
        if selection == "Basement A":
            levels = ["B1", "B2", "B3", "B4", "B5", "B6", "B7"]
        elif selection == "Club Lounge":
            levels = ["53F"]
        elif selection == "Hotel-Luxury":
            levels = ["30F", "31F", "32F", "33F", "34F", "35F", "36F", "37F", "38F", "39F", "40F", "41F", "42F", "43F", "44F"]
        elif selection == "Hotel-Service Apartments":
            levels = ["54F", "55F", "56F", "57F", "58F", "59F", "60F"]
        elif selection == "Hotel-Ultra Luxury":
            # 修正这里的"52"为"52F"
            levels = ["46F", "47F", "48F", "49F","50F", "51F", "52F"]
        elif selection == "Link Levels":
            levels = ["23F", "24F", "25F", "26F"]
        elif selection == "Others":
            levels = ["22F", "23F", "29F", "45F", "67F", "RF", "RF"]
        elif selection == "Penthouses":
            levels = ["61F", "62F", "63F", "64F", "65F", "66F"]
        elif selection == "Podium A":
            levels = ['GF', "1F", "2F","3F"]
        elif selection == "Rental Offices":
            levels = ["5F", "6F", "7F", "8F", "9F", "10F", "11F", "12F", "13F", "14F", "15F","16F","17F","18F","19F","20F","21F"]
        elif selection == "Restaurants":
            levels = ["4F"]
        elif selection == "Spa/Gym":
            levels = ["27F", "28F"]
        elif selection == "Apartments-Duplex":
            levels = ["30F", "31F", "32F", "33F", "34F", "35F", "36F", "37F", "38F", "39F", "40F", "41F", "42F", "43F", "44F", "45", "46F", "47F", "48F", "49F","50F", "51F", "52F", "53F", "54F","55F", "56F","57F","58F"]
        elif selection == "Apartments-Simplex":
            levels = ["5F", "6F", "7F", "8F", "9F","10F","11F","12F","13F","14F","15F","16F","17F","18F","19F","20F","21F","22F","23F","24F","25F","26F"]
        elif selection == "Basement B":
            levels = ["B1","B2","B3","B4","B5","B6","B7"]
        elif selection == "Link":
            levels = ["28F", "29F"]
        elif selection == "Mech & Roof":
            levels = ["RF"]
        elif selection == "Podium B":
            levels = ["GF","1F","2F","4F"]
        else:
            levels = []
        
        self.level_var.set("Select a level")  # 重置楼层选择提示
        self.level_dropdown['menu'].delete(0, 'end')
        for level in levels:
            self.level_dropdown['menu'].add_command(
                label=level,
                command=lambda l=level: [self.level_var.set(l), self.update_room_menu(l)]
            )
    

    def update_room_menu(self, selection):
        if selection == "B1":
            rooms = ["FWT BA 001","FWT BA 002","RAMP 1 BA 003","MECH WATER TANK (WATER FEATURE 13) BA 004"]
        else:
            rooms = []
        self.room_var.set("Select the room")
        self.room_dropdown['menu'].delete(0, 'end')
        for room in rooms:
            self.room_dropdown['menu'].add_command(label=room, command=tk._setit(self.room_var, room))

root = tk.Tk()
app = App(root)
root.mainloop()

• 在update_level_menu中添加了self.level_var.set("Select a level")，每次切换子区域时重置楼层选择的提示文本，体验更友好
• 修正了Hotel-Ultra Luxury中的楼层拼写错误，避免后续选择时无法匹配到正确的楼层列表

内容的提问来源于stack exchange，提问作者hexapod