调用带有“command"参数的函数和“绑定" [英] Calling functions with arguments on "command" and "bind"

问题描述

我想指出的是，我从很短的时间就开始学习 Python.问题将是初学者之一.

i want to point, that i am learning python since short time. The question is going be to beginner one.

我需要在程序顶部的菜单中添加命令，该命令会调用函数color_picker("red").

I need to add command to menu at top of program, which would call function "color_picker("red").

kolory.add_command(label="Czerwony", command=color_picker('red'))当我使用它时，它不知何故错了，因为一旦程序启动它就会被调用，而不是等待我单击菜单按钮.(我确信这一点，因为我向该函数添加了showinfo"，并且在我执行任何操作之前它会显示消息)kolory.add_command(label="Czerwony", command=lambda: color_picker('red')) 那个有点用，但我不知道lambda"在这里是什么意思.它是在菜单选项下使用参数调用函数的唯一方法吗?

kolory.add_command(label="Czerwony", command=color_picker('red')) When i am using that, its somehow wrong, cuz its called once the program started, its not waiting for me to click the menu button. (i am sure of it, as i added "showinfo" to that function, and it shows the message before i do anything) kolory.add_command(label="Czerwony", command=lambda: color_picker('red')) That one kinda works, but i don't know what does "lambda" mean here. Is it only way to call functions with arguments under menu options?

同样的问题涉及绑定键盘快捷键.okno.bind("1", color_picker) - 将调用函数但没有参数，参数应该是颜色.我该怎么做?

Same question goes to binding keyboard shortcuts. okno.bind("1", color_picker) - that will call the function but does not have the argument, which should be a color. How can i do that?

那么，如何使用 add_command 将带参数的函数分配给键盘快捷键和菜单?

So, how to assign functions WITH arguments, to keyboard shortcuts and to menu using add_command?

附注.正在通过谷歌搜索，但似乎 python 没有像 c# 那样好的文档.或者我太笨了找不到.

PS. Was searching trough google, but it seems python does not have so good documentation like c# does for example. Or i am too stupid to find it.

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python27\lib\lib-tk\Tkinter.py", line 1410, in __call__
    return self.func(*args)
TypeError: color_picker() takes at most 1 argument (2 given)

这是错误信息，当我尝试在 okno.bind 中使用pick_red"

Thats the error message, when i try to use "pick_red" in okno.bind

推荐答案

我不确定我是否理解这个问题，但在这里；

I'm not sure if I understand the question, but here goes;

问题在于您正在调用color_picker 函数(通过在函数名称后添加()).

The problem is that you are calling the color_picker function (by adding () after the function name).

你想要做的是传递实际的函数，而不是函数调用的结果作为command关键字参数，例如add_command(label="Czerwony", command=color_picker)

What you want to do is pass the actual function, not the result of the function call as the command keyword argument, e.g. add_command(label="Czerwony", command=color_picker)

然而，因为你想给它一个固定的参数 'red'，你必须使用 partial 来自 functools，类似;

However, since you want to give it a fixed argument 'red', you must use partial from functools, something like;

from functools import partial
pick_red = partial(color_picker, "red")
kolory.add_command(label="Czerwony", command=pick_red)

编辑:

既然您的错误消息显示您正在使用 Tkinter，我们可以根据 documentation 给 bind() 的函数总是传递一个 event 参数，所以你需要一个可以接受的函数；

Now that your error message shows that you are using Tkinter, we can see that according to documentation the function that is given to bind() is always passed an event parameter, so you need a function that can accept it;

def pick_red_with_event(event):
    # We really do nothing with event for now but we always get it...
    color_picker("red")

okno.bind("1", pick_red_with_event)

<打击>okno.bind 同样适用，如果您已经定义了 pick_red 如上所述，只需执行:

Same thing works for okno.bind, if you have defined pick_red as above, just do:

okno.bind("1", pick_red)

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