所有tkinter函数在程序启动时运行 [英] All tkinter functions run when program starts

问题描述

我有一个非常奇怪的问题，在使用tkinter之前我从未有过。无论我为按钮或菜单项等小部件设置命令，该命令都会在应用程序启动时运行。基本上，该命令不会等到单击该小部件才能运行。在我的代码中，我知道我没有打包按钮，这是为了显示小部件甚至不必被拖到屏幕上以发生此问题。有人知道可能是什么原因造成的吗？

I am having a very weird problem that I've never had before when using tkinter. Anywhere that I set a command for a widget such as a button or a menu item, the command runs when the application starts up. Basically the command doesn't wait until the widget is clicked to run. In my code, I know that I did not pack the button, this was to show that widget don't even have to be drawn onto the screen for this problem to occur. Does anybody know what could be causing it? Thanks!

from tkinter import *

class menuItems(object):
    def __init__(self):
        menubar = Menu(app)
        filemenu = Menu(menubar, tearoff=0)
        filemenu.add_command(label="New...", command=self.new())
        filemenu.add_command(label="Open...", command=self.open())
        filemenu.add_command(label="Save", command=self.save())
        filemenu.add_separator()
        filemenu.add_command(label="Exit", command=app.quit)
        menubar.add_cascade(label="File", menu=filemenu)
        app.config(menu=menubar)

    def new(self):
        pass

    def open(self):
        pass

    def save(self):
        print("You have saved the file")

def this_should_not_run():
    print("Yay! I didn't run!")

def this_will_run_even_though_it_should_not():
    print("You can't stop me!")

def init():
    global app, menu
    app = Tk()
    app.title("Words with Python")
    app.geometry("800x500+50+50")

    menu = menuItems()

    frame = Frame(app)
    scrollbar = Scrollbar(frame, orient=VERTICAL)
    textbox = Text(frame, yscrollcommand=scrollbar.set)
    scrollbar.config(command=textbox.yview)
    scrollbar.pack(side=RIGHT, fill=Y)
    textbox.pack(side=LEFT, fill=BOTH, expand=1)
    frame.pack(fill=BOTH, expand=1)

    button = Button(app, text="Nothing", command=this_will_run_even_though_it_should_not())

    return

init()

app.mainloop()

推荐答案

删除命令定义中的（）。现在，您正在调用函数并将返回值绑定到 command 参数，而您需要绑定函数本身，以便稍后调用函数。

Remove the ()s in your command definitions. Right now, you are calling the function and binding the return values to command parameter whereas you need to bind the functions itself so that later on they could be called.

所以这样一行：

So a line like this:

filemenu.add_command(label="New...", command=self.new())

应该是这样的：

filemenu.add_command(label="New...", command=self.new)

（你实际上在一个地方做了这个： filemenu.add_command（label =Exit，command = app.quit） ）

(You actually do this in one place correctly: filemenu.add_command(label="Exit", command=app.quit))

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