Python: Tkinter message Box - Error Handling

python, tkinter

Solution

You can use the `tkMessageBox` module to show error boxes.

from Tkinter import *
import tkMessageBox

def clicked():
    tkMessageBox.showerror("Error", "Please only input whole numbers")

root = Tk()
button = Button(root, text = "show message box", command = clicked)
button.pack()
root.mainloop()

Also any idea how i can limit the input to just Integers?

You can use `validatecommand` to reject input that doesn't fit your specifications.

from Tkinter import *

def validate_entry(text):
    if text == "": return True
    try:
        value = int(text)
    except ValueError: #oops, couldn't convert to int
        return False
    return 0 <= value <= 100

root = Tk()

vcmd = (root.register(validate_entry), "%P")
entry = Entry(root, validate = "key", validatecommand=vcmd)
entry.pack()

root.mainloop()

Problem

I'm looking to use the Tkinter message windows as an error handler. Basically just saying you can only input "x,y,z" It's being used on a program that asks the user for the input, Any integers that are => 0 and =<100 are accepted. At the moment it's working but only displays it on a label. Can anyone suggest anything i can use to input a tkinter error window? Also any idea how i can limit the input to just Integers? Below is the add function that once the user inputs a number and click's add, it fires this function. If i haven't explained this well then please advise me and i'll try to expand on it. ``` def add(): try: value = int(MarkEnt.get()) assert 0 <= value <= 100 mark.set(value) exammarks.append(value) ListStud.insert(len(exammarks),value) except AssertionError: error1.set("Please only input whole numbers from 0 to 100") errorLbl.grid() ```

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