tkinter user input widget to xlsx - python-3.x

Question

How do I write user input from tkinter entry widget to xlsx?
Should I be using a different module?
from tkinter import *
import xlsxwriter
def output():
c = Toplevel(root)
c.title =("Main")
c.geometry =('')
e= Entry(c, width=20).grid(row=0, column=1, sticky=W, padx=10)
l=Label(c, text="Current Value").grid(row = 0, column=0, sticky=W, padx=10)
e2 = Entry(c, width=20).grid(row=1, column=1, sticky=W, padx=10)
l2= Label(c, text="New Value").grid(row = 1, column=0, sticky=W, padx=10)
b=Button(c, text="Submit",command= write_to_xlsx).grid(row= 1, column=2, sticky=E, padx=10)
def write_to_xlsx():
workbook =xlsxwriter.Workbook('tkintertest18.xlsx')
worksheet = workbook.add_worksheet()
worksheet.write_string('C1', 'e2.get()')
workbook.close()
root = Tk()
root.title("Main Menu")
root.geometry('400x400+230+130')
Button(root, text="1", command=output).grid(row =0, column= 2)
root.mainloop()

Answer 1

You should almost always use a class when tkinter is involved. So here is a working prototype of your code above. There were multiple problems. One is that when you slap grid next to your widgets instead of putting them on a new line, grid returns None, not the object. Implementing the app as a class enables the other functions to access the GUI components (in this case self.e2). Another error was you had single-quoted the 'e2.get()' call, which is technically a string. So removing the quotes fixes that. There may have been other things...
import xlsxwriter
class XLwriter:
def __init__(self):
c = Toplevel(root)
c.title =("Main")
c.geometry =('')
self.e= Entry(c, width=20).grid(row=0, column=1, sticky=W, padx=10)
self.l=Label(c, text="Current Value").grid(row = 0, column=0, sticky=W, padx=10)
self.e2 = Entry(c, width=20)
self.e2.grid(row=1, column=1, sticky=W, padx=10)
self.l2= Label(c, text="New Value").grid(row = 1, column=0, sticky=W, padx=10)
self.b=Button(c, text="Submit",command=self.write_to_xlsx).grid(row= 1, column=2, sticky=E, padx=10)
def write_to_xlsx(self):
workbook =xlsxwriter.Workbook('tkintertest18.xlsx')
worksheet = workbook.add_worksheet()
worksheet.write_string('C1', self.e2.get())
workbook.close()
root = Tk()
root.title("Main Menu")
root.geometry('400x400+230+130')
app = XLwriter()
#Button(root, text="1", command=output).grid(row =0, column= 2)
root.mainloop()

Answer 2

Seeing that Ron already provided you with a class to perform this task I will respond with the non-class method of doing this to more closely reflect the current code you have.
Keep in mind that with xlsxwriter there is not a way to read from the spreadsheet so for the entry field you have that is labeled as "Current Value" you will need to use a different excel library to fill that field with data from the spreadsheet.
Make sure if you are going to interact with a widget that you do not use the geometry manager directly with the creation of the widget. This will return None to anything trying to interact with it. Instead on the next line after you have created the widget you can use the widget variable name and then your geometry manager of choice(grid(), pack(), place()). This will allow us to interact with the widget without the issue of None being returned by the geometry manager.
In order for you to be able to interact with e2 outside of the output() function you will need to assign e2 to the global namespace. You can do this by simply adding global e2 inside your output() function.
Note: The use of global is best avoided whenever possible this is one compelling reason to use a more Object Oriented Programing method (class) as the use of global is not needed when using class attributes.
from tkinter import *
import xlsxwriter
root = Tk()
root.title("Main Menu")
#root.geometry('400x400+230+130')
def output():
global e2
c = Toplevel(root)
c.title = ("Main")
e = Entry(c, width = 20)
e.grid(row = 0, column = 1, sticky = W, padx = 10)
l = Label(c, text = "Current Value")
l.grid(row = 0, column = 0, sticky = W, padx = 10)
e2 = Entry(c, width=20)
e2.grid(row = 1, column = 1, sticky = W, padx = 10)
l2 = Label(c, text = "New Value")
l2.grid(row = 1, column = 0, sticky = W, padx = 10)
b = Button(c, text = "Submit",command = write_to_xlsx)
b.grid(row = 1, column = 2, sticky = E, padx = 10)
def write_to_xlsx():
workbook = xlsxwriter.Workbook('tkintertest18.xlsx')
worksheet = workbook.add_worksheet()
worksheet.write_string('C1', e2.get())
workbook.close()
btn = Button(root, text = "1", command = output)
btn.grid(row = 0, column = 2)
root.mainloop()