Problems with Tkinter Entry and .get()

Question

I'm having problems with my Tkinter Entry widget. I'm just testing things out and would like to have my callback print out whatever I typed out in Entry self.a. but I'm getting this error.

File "C:\Python27\lib\lib-tk\Tkinter.py", line 1410, in call return self.func(*args) File "C:/Users/Andy/testimage.py", line 146, in get print a.get(self) NameError: global name 'a' is not defined

I was wondering if someone can tell me what I'm doing wrong. I linked the callback function correctly because if I make it print "aasdfasd" instead, it will print that when I press the button.

def clicked_wbbalance(self):
    self.top = Toplevel()
    self.top.title("LASKJDF...")
    Label(self.top, text="Enter low level").grid(row=0, column=0,padx=10)
    Label(self.top, text="Enter high level").grid(row=1, column=0,padx=10)
    Label(self.top, text="Values must be between 0 to 255").grid(row=3, column=0)
    Button(self.top, text="Ok", command=self.get).grid(row=3, column = 1)

    self.a =Entry(self.top).grid(row=0, column=1,padx=10)
    self.b =Entry(self.top).grid(row=1, column=1,padx=10)

def get(self):
    print self.a.get(self)

Steven Rumbalski Steven Rumbalski · Accepted Answer · 2012-11-11T22:31:51

As RocketDonkey pointed out, your traceback does not match the code you posted.

Your code as written will generate a traceback like this:

AttributeError: 'NoneType' object has no attribute 'get'

The root problem is that grid returns None. That means that attributes a and b will be None because they are assigned the result of calls to grid. Fix that by puting object creation and widget placement on different lines:

self.a = Entry(self.top)
self.b = Entry(self.top)

self.a.grid(row=0, column=1,padx=10)
self.b.grid(row=1, column=1,padx=10)

Problems with Tkinter Entry and .get()

2 Answers