python开发_tkinter_获取文本框内容_给文本框添加键盘输入事件

在之前的blog中有提到python的tkinter中的菜单操作

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下面是tkinter的获取文本框内容_给文本框添加键盘输入事件的操作

运行效果：

在输入的时候，单击回车键，触发：print_contents()

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代码部分：

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 from tkinter import *

 __author__ = {'name' : 'Hongten',
               'mail' : 'hongtenzone@foxmail.com',
               'blog' : 'http://www.cnblogs.com/',
               'QQ': '',
               'created' : '2013-09-11'}

 # This program  shows how to make a typein box shadow a program variable.
 flag = True
 class App(Frame):
     def __init__(self, master=None):
         Frame.__init__(self, master)
         self.pack()

         self.entrythingy = Entry(self)
         self.entrythingy.pack()

         self.button = Button(self, text="Uppercase The Entry",
                              command=self.upper)
         self.button.pack()

         # here we have the text in the entry widget tied to a variable.
         # changes in the variable are echoed in the widget and vice versa.
         # Very handy.
         # there are other Variable types. See Tkinter.py for all
         # the other variable types that can be shadowed
         self.contents = StringVar()
         self.contents.set("this is a variable")
         self.entrythingy.config(textvariable=self.contents)

         # and here we get a callback when the user hits return. we could
         # make the key that triggers the callback anything we wanted to.
         # other typical options might be <Key-Tab> or <Key> (for anything)
         self.entrythingy.bind('<Key-Return>', self.print_contents)

     def upper(self):
         # notice here, we don't actually refer to the entry box.
         # we just operate on the string variable and we
         # because it's being looked at by the entry widget, changing
         # the variable changes the entry widget display automatically.
         # the strange get/set operators are clunky, true...
         global flag
         flag = not flag
         if not flag:
             str = self.contents.get().upper()
             self.contents.set(str)
         else:
             str = self.contents.get().lower()
             self.contents.set(str)
         print('the contents is : ', self.contents.get())

     def print_contents(self, event):
         print("hi. contents of entry is now ---->", self.contents.get())

 root = App()
 root.master.title("Foo")
 root.mainloop()

参考资料：

http://www.oschina.net/code/explore/Python-3.1.3/Demo/tkinter/matt/entry-with-shared-variable.py