要从python 3中的文本框中获取Tkinter输入，我使用的完整学生级程序如下：
#Imports all (*) classes,
#atributes, and methods of tkinter into the
#current workspace
from tkinter import *
#***********************************
#Creates an instance of the class tkinter.Tk.
#This creates what is called the "root" window. By conventon,
#the root window in Tkinter is usually called "root",
#but you are free to call it by any other name.
root = Tk()
root.title('how to get text from textbox')
#**********************************
mystring = StringVar()
####define the function that the signup button will do
def getvalue():
## print(mystring.get())
#*************************************
Label(root, text="Text to get").grid(row=0, sticky=W) #label
Entry(root, textvariable = mystring).grid(row=0, column=1, sticky=E) #entry textbox
WSignUp = Button(root, text="print text", command=getvalue).grid(row=3, column=0, sticky=W) #button
############################################
# executes the mainloop (that is, the event loop) method of the root
# object. The mainloop method is what keeps the root window visible.
# If you remove the line, the window created will disappear
# immediately as the script stops running. This will happen so fast
# that you will not even see the window appearing on your screen.
# Keeping the mainloop running also lets you keep the
# program running until you press the close buton
root.mainloop()
