未正确读取复选框值
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【中文标题】未正确读取复选框值【英文标题】：Checkbox values not being read properly 【发布时间】：2016-03-06 06:17:50 【问题描述】：我有一个从数据库获取信息的 Python 程序；在这种情况下，我们正在预订酒店。我的问题是，如果我使用复选框并选择多个房间 - 只会显示列表中的第一个房间。我认为该错误是我的 checkDetails 方法中存在的各种计数错误。
它会出现，然后在尝试获取复选框的值时，它仅适用于列表中的第一个复选框。老实说，我不是 100% 确定如何描述这个问题。我已经上传了四个 GIF 来代替文字。
好： Selecting the first two works fine. Selecting the first item alone works as well. No matter what, the first item always works.
BAD_1：Selecting the first item and another item (any item except the second) only displays the first item regardless.
BAD_2：Selecting any two items that don't involve the first item, results in neither item being displayed.
BAD_3：Selecting any single item that isn't the first item results in it not being displayed.
##(USER)MAKE NEW RESERVATION##
def searchReservation(self):
self.root = tk.Tk()
self.root.title("Search Rooms")
# city option button
self.cityvariable = StringVar(self.root)
self.cityvariable.set("Select City")
w = OptionMenu(self.root, self.cityvariable, "Atlanta", "Charlotte",
"Savannah", "Orlando", "Miami").grid(row=0, column=0)
# start and end labels
self.startDate = tk.Label(
self.root, text="Start Date (YYYY-MM-DD)") .grid(row=1, column=0)
self.endDate = tk.Label(
self.root, text="End Date (YYYY-MM-DD)").grid(row=1, column=1)
# start and end entries
self.startStringEntry = tk.Entry(self.root, state=NORMAL, width=10)
self.startStringEntry.grid(row=2, column=0)
self.startStringEntry.insert(0, '2015-11-23') #TODO debugging--remove
self.endStringEntry = tk.Entry(self.root, state=NORMAL, width=10)
self.endStringEntry.grid(row=2, column=1)
self.endStringEntry.insert(0, '2015-11-25') #TODO debugging--remove
# search button
self.search_button = tk.Button(
self.root, text="Search Availabilities", command=self.makeReservation)
self.search_button.grid()
self.root.mainloop()
def validDate(self, date):
correctdate = None
try:
startdate = datetime.datetime.strptime(date, "%Y-%m-%d")
correctdate = True
except ValueError:
correctdate = False
if correctdate is False:
messagebox.showerror(
title="Warning", message="A valid date format is required.")
return correctdate
def makeReservation(self):
if self.startStringEntry.get() == self.endStringEntry.get():
messagebox.showerror(
title="Warning", message="Reservation must be at least a day")
elif not self.validDate(self.startStringEntry.get()) or not self.validDate(self.endStringEntry.get()):
return
elif datetime.datetime.strptime(self.startStringEntry.get(), '%Y-%m-%d') > datetime.datetime.strptime(self.endStringEntry.get(), '%Y-%m-%d'):
messagebox.showerror(
title="Warning", message="End date must be after start date")
else:
self.search_button.config(state='disabled')
self.root.withdraw()
self.makeRes = tk.Tk()
self.makeRes.title("Make a Reservation")
# date labels
Label(self.makeRes, text="Start Date") .grid(row=0, column=0)
Label(self.makeRes, text="End Date").grid(row=0, column=1)
Label(self.makeRes, text=self.startStringEntry.get()).grid(
row=1, column=0)
Label(self.makeRes, text=self.endStringEntry.get()).grid(
row=1, column=1)
Label(self.makeRes, text='City').grid(row=0, column=2)
Label(self.makeRes, text=self.cityvariable.get()).grid(
row=1, column=2)
# column headers
roomnumber = tk.Label(
self.makeRes, text="Room Number").grid(row=2, column=0)
roomcat = tk.Label(self.makeRes, text="Room Category").grid(
row=2, column=1)
capacity = tk.Label(
self.makeRes, text="Room Capacity").grid(row=2, column=2)
costperday = tk.Label(
self.makeRes, text="Cost Per Day").grid(row=2, column=3)
costextra = tk.Label(
self.makeRes, text="Extra Bed Cost").grid(row=2, column=4)
availability = tk.Label(
self.makeRes, text="Select Room").grid(row=2, column=5)
# insert available rooms
sql = """SELECT a.RoomNum, a.Category, b.RoomCapacity, a.CostPerDay, a.ExtraBedCost
FROM ROOM a, ROOM_CAPACITY b
WHERE a.Category = b.Category
AND a.RoomLocation = '""" + self.cityvariable.get() + """'
AND (
a.RoomNum, a.RoomLocation
) NOT
IN (
SELECT DISTINCT c.RoomNum, c.Location
FROM ROOM_RESERVATION c, RESERVATION d
WHERE c.ReservationID = d.ReservationID
AND c.Location = a.RoomLocation
AND d.RefundAmount IS NULL
AND """ + self.endStringEntry.get() + """ <= d.EndDate
AND """ + self.startStringEntry.get() + """ >= d.StartDate
)"""
cursor.execute(sql)
self.count = 3
self.data = []
for data in cursor:
self.data.append(data)
for i in range(5):
Label(self.makeRes, text=data[i]).grid(
row=self.count, column=i)
self.count = self.count + 1
if self.count == 3:
messagebox.showerror(
title="Warning", message="No rooms available for city and dates")
self.makeRes.destroy()
self.searchReservation()
else:
# making checkboxes to select room
self.vars = []
for rowNum in range(3, self.count):
self.var = IntVar(self.makeRes)
Checkbutton(self.makeRes, variable=self.var).grid(
row=rowNum, column=5)
self.vars.append(self.var)
self.check_detail_button = Button(
self.makeRes, text='Check Details', command=self.checkDetails)
self.check_detail_button.grid(row=self.count + 1, column=5)
def checkDetails(self):
noneselected = True
for i in self.vars:
if i.get() == 1:
noneselected = False
break
if noneselected is True:
messagebox.showerror(title="Warning", message="No rooms selected")
else:
self.check_detail_button.config(state='disabled')
ttk.Separator(self.makeRes, orient=HORIZONTAL).grid(
column=0, row=self.count+2, columnspan=10, sticky=(W, E))
# column headers
Label(self.makeRes, text="Room Number").grid(
row=self.count + 3, column=0)
Label(self.makeRes, text="Room Category").grid(
row=self.count + 3, column=1)
Label(self.makeRes, text="Room Capacity").grid(
row=self.count + 3, column=2)
Label(self.makeRes, text="Cost Per Day").grid(
row=self.count + 3, column=3)
Label(self.makeRes, text="Extra Bed Cost").grid(
row=self.count + 3, column=4)
Label(self.makeRes, text="Select Extra Bed").grid(
row=self.count + 3, column=5)
self.count += 4
new_count = 0
for data in self.data:
print(data, self.vars[new_count].get()) #TODO remove
if self.vars[new_count].get() == 1:
for i in range(5):
Label(self.makeRes, text=data[i]).grid(
row=self.count + new_count, column=i)
new_count += 1
# making checkboxes to select beds
self.beds = []
count = 0
for rowNum in range(self.count, self.count + new_count):
if self.vars[count].get() == 1:
var = IntVar(self.makeRes)
checkBox = tk.Checkbutton(
self.makeRes, variable=var).grid(row=rowNum, column=5)
self.beds.append(var)
count += 1
self.count += new_count
Label(self.makeRes, text='Total Cost').grid(
row=self.count + 1, column=2)
# CALCULATE TOTAL COSTS
total_cost = 0
count = 0
self.new_data = []
for i in self.data:
if self.vars[count].get() == 1:
total_cost += i[3]
self.new_data.append(i)
count += 1
val = str(total_cost)
self.total_costs_entry = Entry(self.makeRes)
self.total_costs_entry.grid(row=self.count + 1, column=3)
self.total_costs_entry.insert(0, val)
self.total_costs_entry.config(state='readonly')
Button(self.makeRes, text='Update total', command=self.updateTotalCosts).grid(
row=self.count + 1, column=4)
Label(self.makeRes, text='Use Card').grid(
row=self.count + 2, column=2)
cursor.execute(
'SELECT CardNum FROM PAYMENT_INFO WHERE Username="' + self.user + '"')
cards = ['-']
for i in cursor:
cards.append(i)
self.card = StringVar(self.makeRes)
self.opts = OptionMenu(self.makeRes, self.card, *cards)
self.opts.grid(row=self.count + 2, column=3)
Button(self.makeRes, text="Add Card", command=self.addCreditCard).grid(
row=self.count + 2, column=4)
Button(self.makeRes, text="Delete Card", command=self.deleteCard).grid(
row=self.count + 2, column=5)
Button(self.makeRes, text='Submit', command=self.submitReservation).grid(
row=self.count + 3, column=5)
def updateTotalCosts(self):
total_cost = 0
count = 0
self.new_data = []
for i in self.data:
if self.vars[count].get() == 1:
total_cost += i[3]
self.new_data.append(i)
count += 1
count = 0
for i in self.new_data:
if self.beds[count].get() == 1:
total_cost += i[4]
count += 1
cursor.execute("SELECT DATEDIFF(%s, %s)",
(self.endStringEntry.get(), self.startStringEntry.get()))
diff = cursor.fetchone()
diff = diff[0]
total_cost = diff * total_cost
self.total_costs_entry.destroy()
self.total_costs_entry = Entry(self.makeRes)
self.total_costs_entry.grid(row=self.count + 1, column=3)
self.total_costs_entry.insert(0, str(total_cost))
self.total_costs_entry.config(state='readonly')
编辑：为什么不这样做？
for data in self.data:
print(data, self.vars[new_count].get()) #TODO debugging--remove
if self.vars[new_count].get() == 1:
for i in range(5):
Label(self.makeRes, text=data[i]).grid(
row=self.count + new_count, column=i)
new_count += 1
【问题讨论】：
(Wince) 像这样把界面和后端代码混在一起真是让人头疼；将代码分成几层是一个非常好的主意——一层用于与数据库通信，一层用于业务逻辑，一层用于接口代码。它将为您节省很多问题。 @HughBothwell 我知道。这部分其实不是我写的；一位团队成员对此部分进行了编码，我正在尝试为她解决它。两个小时后，我一无所获。 你做过任何调试吗？例如，您确定self.data 是否包含您认为在checkDetails 内部的数据？
@BryanOakley 如果您查看代码，您会注意到我有一个打印语句，它显示复选框的值和 self.data 的内容。复选框的值不是我所期望的——否则这将起作用。数据正确。
【参考方案1】：
绝对的一个问题是您创建了多个tk.Tk() 的实例。 Tkinter 并非旨在以这种方式工作，它会产生与您所看到的类似的问题。
如果您需要额外的窗口，您必须创建tk.Toplevel 的实例。
另一个问题是这个循环：
for data in self.data:
if self.vars[new_count].get() == 1:
for i in range(5):
Label(self.makeRes, text=data[i]).grid(
row=self.count + new_count, column=i)
new_count += 1
逻辑上存在根本缺陷。即使您遍历数据，您仍会继续检查self.vars[new_count]。因此，即使您最终登陆数据项 3、4、5 等，您仍会一遍又一遍地检查self.vars[0]。一旦你找到一个选中的项目，你现在继续查看self.vars[1]，即使你现在可能在数据项编号 3、4、5 等上。
一个简单的解决方法是确保您对变量的迭代与对数据值的迭代相同：
for var, data in zip(self.vars, self.data):
if var.get() == 1:
for i in range(5):
Label(self.makeRes, text=str(data[i]) + "?").grid(
row=self.count + new_count, column=i)
new_count += 1
以上假设self.vars 中的项目与self.data 中的项目之间存在1:1 的关系。很难说这是否是一个有效的假设。
【讨论】：
就像我说的——我没有写这段代码。我不想大修它；这个答案让我更接近解决我的问题。我意识到代码有其缺陷——但我非常怀疑tk.Tk() 的多个实例。
我按照你说的做了——但仍然有同样的问题。
@Nxt3：我不是在责怪你。不管是谁写的代码，它都有一个致命的缺陷。这不仅仅是装饰，您实际上是在创建一个新的 tcl 解释器并丢弃旧的解释器，这可能会导致您丢失检查按钮的值等。无论如何，我在代码中发现了另一个错误，我已经更新了我的答案。
我应该补充一点，在整个程序中修复多个 tk.Tk() 已经解决了我遇到的另一个问题。感谢您引起我的注意！我觉得我最初的评论有点苛刻。你是对的——这是一个问题。
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