通过curselection（）Tkinter更改背景颜色

Question

I'm facing an issue trying to change the background color by selecting it in the OptionMenu . The colors just don't change even if I add an else clause.

root=Tk()
root.geometry("200x200")
variative=IntVar()        
list=[1,2,3,4]
variative.set('Select')
listbox=OptionMenu(root,variative,list[0],list[1],list[2],list[3])
def Background(event):
    l=listbox.curselection()
    if l==1:
        root.config(bg='red')
    elif l==2:
        root.config(bg='yellow')
    elif l==3:
        root.config(bg='gray')
    elif l==4:
        root.config(bg='green')    
listbox.bind('<<ListboxSelect>>',Background)
listbox.pack()
root.mainloop()

Answer 1

An OptionMenu is not a Listbox , that's why the <<ListboxSelect>> event never happens. However, you can pass a command option to the OptionMenu when you create it. This command will be called each time an option is selected in the menu and the selected option will be passed in argument.

Here is an example:

from tkinter import Tk, OptionMenu, IntVar
root = Tk()
variative = IntVar()        
option_list = [1,2,3,4]
variative.set('Select')

def background(sel):
    if sel == 1:
        root.config(bg='red')
    elif sel == 2:
        root.config(bg='yellow')
    elif sel == 3:
        root.config(bg='gray')
    elif sel == 4:
        root.config(bg='green')   

listbox = OptionMenu(root,variative, *option_list, command=background)
listbox.pack()
root.mainloop()