请帮我处理全局变量

Question

这是我的代码，我一直在学习这个家伙的教程https://www.youtube.com/watch?v=YXPyB4XeYLA&t=13094s@下午4:35:30

我坚持的部分是当他谈到使用全局变量时。

每当我按下更新记录时，它都会显示错误消息

第80行，更新中"first"：f_name_editor.get((，名称错误：名称"f_name_editor"未定义

所以我回去查看全局变量，上面写着：

模块级未定义全局变量"f_name_editor">

我已经没有主意了，但我还是想不通。我遵循了所有的步骤，来回查看我在视频中是否遗漏了什么，但我仍然找不到问题

请帮帮我！

from tkinter import *
import sqlite3
root = Tk()
root.title('Family Member List')
root.geometry('400x400')
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()

'''
c.execute("""CREATE TABLE family(
first_name text,
last_name text,
gender text,
occupation text
)
#""")
'''
#Edit function to update record
def edit():
editor = Tk()
editor.title('Update Record')
editor.geometry('400x400')
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()
record_id = delete_box.get()
c.execute("SELECT * FROM family WHERE oid =" + record_id)
records = c.fetchall()
global f_name_editor
f_name_editor = Entry(editor,width=30)
f_name_editor.grid(row=0, column=1, padx=20)
l_name_editor = Entry(editor,width=30)
l_name_editor.grid(row=1, column=1, padx=20)
gender_editor = Entry(editor,width=30)
gender_editor.grid(row=2, column=1, padx=20)
occupation_editor = Entry(editor,width=30)
occupation_editor.grid(row=3, column=1, padx=20)

f_name_label = Label(editor,text= 'First Name')
f_name_label.grid(row=0, column =0)
l_name_label = Label(editor,text= 'Last Name')
l_name_label.grid(row=1, column =0)
gender_label = Label(editor,text= 'Gender')
gender_label.grid(row=2, column =0)
occupation_label = Label(editor,text= 'Occupation')
occupation_label.grid(row=3, column =0)
# LOOP THROUGH RESULT
for record in records:
f_name_editor.insert(0, record[0])
l_name_editor.insert(0, record[1])
gender_editor.insert(0, record[2])
occupation_editor.insert(0, record[3])
#Save Button after edited
edit_btn = Button(editor, text='Save Record', command = update)
edit_btn.grid(row=6, column = 1, columnspan = 2, pady=10, padx = 10, ipadx= 100)
def update():
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()
record_id = delete_box.get()
c.execute('''UPDATE family SET
first_name=:first,
last_name=:last,
gender=:gender,
occupation=:occupation
WHERE oid = :oid''',
{
'first': f_name_editor.get(),
'last': l_name_editor.get(),
'gender': gender_editor.get(),
'occupation': occupation_editor.get(),
'oid': record_id
})
conn.commit()
conn.close()

def delete():
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()
c.execute("DELETE from family WHERE oid=" + delete_box.get())
conn.commit()
conn.close()
def submit():
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()
c.execute("INSERT INTO family VALUES (:f_name,:l_name,:gender,:occupation)",
{
'f_name':f_name.get(),
'l_name':l_name.get(),
'gender': gender.get(),
'occupation': occupation.get(),
})
conn.commit()
conn.close()
f_name.delete(0,END)
l_name.delete(0,END)
gender.delete(0,END)
occupation.delete(0,END)
def query():
conn = sqlite3.connect('Family_list.db')
c = conn.cursor()
c.execute('SELECT *, oid FROM family')
records = c.fetchall()
print(records)
conn.commit()
conn.close()
print_records = ''
for record in records:
print_records += str(record[0]) + " t "+ str(record[4]) +'n'
query_label = Label(root,text= print_records)
query_label.grid(row = 8 ,column = 0, columnspan =2 )

f_name = Entry(root,width=30)
f_name.grid(row=0, column=1, padx=20)
l_name = Entry(root,width=30)
l_name.grid(row=1, column=1, padx=20)
gender = Entry(root,width=30)
gender.grid(row=2, column=1, padx=20)
occupation = Entry(root,width=30)
occupation.grid(row=3, column=1, padx=20)
delete_box= Entry(root, width=30)
delete_box.grid(row=9, column = 1)

#create global variable

f_name_label = Label(root,text= 'First Name')
f_name_label.grid(row=0, column =0)
l_name_label = Label(root,text= 'Last Name')
l_name_label.grid(row=1, column =0)
gender_label = Label(root,text= 'Gender')
gender_label.grid(row=2, column =0)
occupation_label = Label(root,text= 'Occupation')
occupation_label.grid(row=3, column =0)
delete_box_label = Label(root, text = 'Select ID Number')
delete_box_label.grid(row=9, column= 0)
#BUTTONS
submit_btn = Button(root,text='Add Record to Database', command= submit)
submit_btn.grid(row = 4, column =0, columnspan=2, pady=10, padx =10, ipadx=100)
query_btn = Button(root, text='Check Submission', command = query)
query_btn.grid(row=5, column = 0, columnspan = 2, pady=10, padx = 10, ipadx= 100)
delete_btn = Button(root, text='Delete Record', command = delete)
delete_btn.grid(row=10, column = 0, columnspan = 2, pady=10, padx = 10, ipadx= 100)
#Update Button
edit_btn = Button(root, text='Update Record', command = update)
edit_btn.grid(row=11, column = 0, columnspan = 2, pady=10, padx = 10, ipadx= 100)

conn.commit()
conn.close()
root.mainloop()

Answer 1

f_name_editor在edit函数创建之前不存在于全局作用域中。调用update函数的代码路径不通过edit函数，因此全局变量此时不存在。您可以在全局范围内声明它，但您可能会发现这只会导致更多的错误。