Python 获取ttk.Combobox中选定项的索引

我在使用Tkinter时使用组合框时遇到了IF语句的问题。当我想让程序选择速度距离时间时，程序会选择速度加速时间和下拉列表中的所有其他公式。你能帮我做这个吗

dropdown = Combobox(root)
dropdown['values']=("Speed, Distance, Time", "Speed, Acceleration, Time", "Gravitational Potential Energy(Ep)", "Kinetic Energy (Ek)", "Elastic Potential Energy (Ee)", "Energy/Work Done, Power, Time", "Energy/Work Done, Force, Distance", "Energy, Voltage, Charge", "Specific Heat Capacity", "Specific Latent Heat", "Efficency", "Pover, Voltage, Current", "Power, Current, Resistance", "Current, Charge, Time", "Voltage, Current, Resistance")
dropdown.pack()

def clicked():    
    if dropdown['values'][0] == dropdown_formulae[0][0]: # if the user has selected the first option
        simpleFormulaMenu(0)
    elif dropdown['values'][1] == dropdown_formulae[1][0]:
        simpleFormulaMenu(1)
    elif dropdown['values'][2] == dropdown_formulae[2][0]:
        pass
    elif dropdown['values'][3] == dropdown_formulae[3][0]:
        pass
    elif dropdown['values'][4] == dropdown_formulae[4][0]:
        pass
    elif dropdown['values'][5] == dropdown_formulae[5][0]:
        simpleFormulaMenu(5)
    elif dropdown['values'][6] == dropdown_formulae[6][0]:
        simpleFormulaMenu(6)
    elif dropdown['values'][7] == dropdown_formulae[7][0]:
        simpleFormulaMenu(7)
    elif dropdown['values'][8] == dropdown_formulae[8][0]:
        pass
    elif dropdown['values'][9] == dropdown_formulae[9][0]:
        pass
    elif dropdown['values'][10] == dropdown_formulae[1][0]:
        pass
    elif dropdown['values'][11]:
        simpleFormulaMenu(11)
    elif dropdown['values'][12]:
        simpleFormulaMenu(12)
    elif dropdown['values'][13]:
        simpleFormulaMenu(13)



button = tk.Button(text = "Submit", command = clicked)
button.pack()

问题：在

ttk.组合框中获取所选项目的索引

---

核心点：使用

索引

获取所选项目的索引

---

参考

• 返回值等于x的第一项的seq中基于零的索引

• .get（）

  方法返回

  组合框的当前选定项

• 将虚拟事件
  绑定到Combobox小部件

---

使用Python:3.5-“Tcl版本”：8.6“TkVersion”：8.6测试

问题：在

ttk.组合框中获取所选项目的索引

---

核心点：使用

索引

获取所选项目的索引

---

参考

• 返回值等于x的第一项的seq中基于零的索引

• .get（）

  方法返回

  组合框的当前选定项

• 将虚拟事件
  绑定到Combobox小部件

---

---

用Python测试：3.5-“TclVersion”：8.6“TkVersion”：8.6

您应该在

下拉列表中获取所选项目：例如
selected=dropdown.get（）
，然后在那些if语句中使用
selected
，而不是
dropdown['values'[…]
。我应该如何在IF语句中使用selected您应该在
下拉列表中获取所选项目：例如
selected=dropdown.get（）
，然后在那些IF语句中使用
selected
，而不是在
dropdown['values'][…]中使用selected
。我应该如何在IF语句中使用selected
import tkinter as tk
import tkinter.ttk as ttk


class App(tk.Tk):
    def __init__(self):
        super().__init__()
        
        self.combobox = combobox = ttk.Combobox(self)
        combobox['values'] = ("Speed, Distance, Time",
                              "Speed, Acceleration, Time",
                              "Gravitational Potential Energy(Ep)"
                              )
        combobox.pack()
        
        button = tk.Button(text="Submit", command=self.on_clicked)
        button.pack()
    
    def on_clicked(self, *event):
        selected = self.combobox.get()
        if selected:
            idx = self.combobox['values'].index(selected)
            print('simpleFormulaMenu({}), selected: {}'.format(idx, selected))
            
            if idx in (2, 3, 4):  # pass
                pass
            else:
                # simpleFormulaMenu(idx)
                pass


if __name__ == '__main__':
    App().mainloop()