事件处理模型

GUI组件根据用户的交互情况生成事件

异步事件驱动的程序：程序将事件绑定到图形组件上，并实现了事件的处理程序（回调函数）来处理GUI事件

 

文本框

用于输入文本，程序员用来显示文本

通过Entry类创建

用户按下Enter键触发Entry组件的<Return>事件

1 # SimpleEntry.py 2 # Entry compnents and event binding demonstration 3  4 from Tkinter import * 5 from tkMessageBox import * 6  7 class EntryDemo( Frame ): 8     """ Demonstrate Entrys and Event binding """ 9 10     def __init__(self):11         """ Create, pack and bind events to four Entrys """12 13         Frame.__init__( self )14         self.pack( expand = YES, fill = BOTH )15         self.master.title( "Testing Entry Components" )16         self.master.geometry( "325x100" ) # width x length17 18         self.frame1 = Frame( self )19         self.frame1.pack( pady = 5 )20 21         self.text1 = Entry( self.frame1, name = "text1" )22 23         # bind the Entry component to event24         self.text1.bind( "
     
      ", self.showContents )25         self.text1.pack( side = LEFT, padx = 5 )26 27         self.text2 = Entry( self.frame1, name = "text2" )28 29         # insert text into Entry component text230         self.text2.insert( INSERT, "Enter text here" )31         self.text2.bind("
      
       ", self.showContents )32         self.text2.pack( side = LEFT, padx = 5 )33 34         self.frame2 = Frame( self )35         self.frame2.pack( pady = 5 )36 37         self.text3 = Entry( self.frame2, name = "text3" )38         self.text3.insert( INSERT, "Uneditable text field" )39 40         # prohibit user from altering text in Entry component text341         self.text3.config( state = DISABLED )42         self.text3.bind("
       
        ", self.showContents )43         self.text3.pack( side = LEFT, padx = 5 )44 45         # text in Entry component text4 appears as *46         self.text4 = Entry(self.frame2, name = "text4", show = "*" )47         self.text4.bind("
        
         ", self.showContents )48         self.text4.pack( side = LEFT, padx = 5 )49 50     def showContents( self, event ):51         """ Display the contents of the Entry """52 53         # acquire name of Entry component that genereated event54         theName = event.widget.winfo_name()55 56         # acquire contents of Entry component that generated event57         theContents = event.widget.get()58         showinfo( "Message", theName + ":" + theContents)59 60 61 demo = EntryDemo()62 63 demo.mainloop()