Python 将变量从combobox传递给被调用函数

我试图将一个变量从tkinter组合框传递到单击“运行”按钮时调用的函数。我对python比较陌生，我尝试的每个选项都会产生一个错误——主要是变量没有定义。我相信这是因为我没有在正确的地方定义它。非常感谢您的帮助

from tkinter import *
from tkinter import ttk
from URL_Generator import crawl_site

listFile = open('regions1.txt','r')

root = Tk()
root.configure()
varItems = StringVar(root, value='')

class MainWindow(Frame):
    def __init__(self,master = None):
        Frame.__init__(self,master)
        self.master = master
        self.grid()
        self.create_widgets()

    def create_widgets(self):
        """Create Window Layout"""
        self.label = Label(self, text="List Items").pack()
        self.itemCombo = ttk.Combobox(self, width = 16, textvariable = varItems)
        self.itemCombo.bind("<Return>", self.itemCombo_onEnter)
        self.itemCombo.bind('<<ComboboxSelected>>',self.itemCombo_onEnter)
        self.itemCombo['values'] = [l.strip() for l in listFile.readlines()]
        self.itemCombo.pack()
        self.blank = Label(self,text='').pack()

        """I want to pass the value selected in the combobox to the crawl_region() function when pushing Run"""

        self.RunButton = Button(self, text="Run",command = crawl_site.crawl_region(region))
        self.RunButton.pack()

    def itemCombo_onEnter(self,event):
        varItems.set(varItems.get().lower().strip())
        mytext = varItems.get().strip()
        vals = self.itemCombo.cget('values')
        self.itemCombo.select_range(0,END)
        print(mytext)
        region = mytext

        """I want to pass mytext to the function called when pushing Run"""

        if not vals:
            self.itemCombo.configure(values = (mytext,))
        elif mytext not in vals:
            with open('regions1.txt', 'w') as f:
                self.itemCombo.configure(values=vals + (mytext,))
                f.write("\n".join(vals + (mytext,)))
                f.close()
        return 'break'

app = MainWindow(root)
root.mainloop()

传递的区域[]会立即返回，但当我进行选择或按下运行按钮时，不会发生任何事情。

请尝试以下代码。 我创建了一个类属性

self.mytext

，它是在输入组合按钮

itemCombo\u oneter

时设置的。按下按钮时，调用

onRunButton

函数。如果设置了

self.mytext

，它将调用

crawl\u区域

函数，并将

self.mytext

作为参数

from tkinter import *
from tkinter import ttk
from URL_Generator import crawl_site

listFile = open('regions1.txt','r')

root = Tk()
root.configure()
varItems = StringVar(root, value='')

class MainWindow(Frame):
    def __init__(self,master = None):
        Frame.__init__(self,master)
        self.master = master
        self.grid()
        self.create_widgets()

    def create_widgets(self):
        """Create Window Layout"""
        self.label = Label(self, text="List Items").pack()
        self.itemCombo = ttk.Combobox(self, width = 16, textvariable = varItems)
        self.itemCombo.bind("<Return>", self.itemCombo_onEnter)
        self.itemCombo.bind('<<ComboboxSelected>>',self.itemCombo_onEnter)
        self.itemCombo['values'] = [l.strip() for l in listFile.readlines()]
        self.itemCombo.pack()
        self.blank = Label(self,text='').pack()

        """I want to pass the value selected in the combobox to the crawl_region() function when pushing Run"""

        self.RunButton = Button(self, text="Run",command = self.onRunButton)
        self.RunButton.pack()

    def onRunButton(self):
        if self.mytext:
            crawl_site.crawl_region(self.mytext)        

    def itemCombo_onEnter(self,event):
        varItems.set(varItems.get().lower().strip())
        mytext = varItems.get().strip()
        vals = self.itemCombo.cget('values')
        self.itemCombo.select_range(0,END)
        print(mytext)

        self.mytext = mytext
        """I want to pass mytext to the function called when pushing Run"""

        if not vals:
            self.itemCombo.configure(values = (mytext,))
        elif mytext not in vals:
            with open('regions1.txt', 'w') as f:
                self.itemCombo.configure(values=vals + (mytext,))
                f.write("\n".join(vals + (mytext,)))
                f.close()
        return 'break'

app = MainWindow(root)
root.mainloop()

这会立即调用方法

crawl\u region

，并将该区域作为参数，并尝试将按钮的回调设置为该方法的结果

---

另一种在不创建其他函数的情况下“修复”问题的方法是使用lambda，但我认为我的方法更具可读性。

如果您遇到错误，应该显示出来。@DanielRoseman-感谢您的快速响应！我已经编辑了这个问题。在这个示例中，我没有得到错误，但是函数在没有按下按钮的情况下被调用，并且返回一个空列表，因为还没有进行选择。我相信我的问题在于代码的顺序。谢谢你的帮助，特别是解释为什么我的代码不起作用（这是一个巨大的帮助）！当我运行更正后的代码时，我得到一个“NameError:name'onRunButton'未定义错误。你能帮我克服这个错误吗？@Justin Hill，

onRunButton

是一个类方法，所以当你声明

self.RunButton

时，你需要

self.onRunButton

作为

命令

参数。

from tkinter import *
from tkinter import ttk
from URL_Generator import crawl_site

listFile = open('regions1.txt','r')

root = Tk()
root.configure()
varItems = StringVar(root, value='')

class MainWindow(Frame):
    def __init__(self,master = None):
        Frame.__init__(self,master)
        self.master = master
        self.grid()
        self.create_widgets()

    def create_widgets(self):
        """Create Window Layout"""
        self.label = Label(self, text="List Items").pack()
        self.itemCombo = ttk.Combobox(self, width = 16, textvariable = varItems)
        self.itemCombo.bind("<Return>", self.itemCombo_onEnter)
        self.itemCombo.bind('<<ComboboxSelected>>',self.itemCombo_onEnter)
        self.itemCombo['values'] = [l.strip() for l in listFile.readlines()]
        self.itemCombo.pack()
        self.blank = Label(self,text='').pack()

        """I want to pass the value selected in the combobox to the crawl_region() function when pushing Run"""

        self.RunButton = Button(self, text="Run",command = self.onRunButton)
        self.RunButton.pack()

    def onRunButton(self):
        if self.mytext:
            crawl_site.crawl_region(self.mytext)        

    def itemCombo_onEnter(self,event):
        varItems.set(varItems.get().lower().strip())
        mytext = varItems.get().strip()
        vals = self.itemCombo.cget('values')
        self.itemCombo.select_range(0,END)
        print(mytext)

        self.mytext = mytext
        """I want to pass mytext to the function called when pushing Run"""

        if not vals:
            self.itemCombo.configure(values = (mytext,))
        elif mytext not in vals:
            with open('regions1.txt', 'w') as f:
                self.itemCombo.configure(values=vals + (mytext,))
                f.write("\n".join(vals + (mytext,)))
                f.close()
        return 'break'

app = MainWindow(root)
root.mainloop()

self.RunButton = Button(self, text="Run",command = crawl_site.crawl_region(region))