Widget.destroy() 在 tkinter python 中不起作用

Question

While users sign up I'm making sure that no required entry fields are empty ie no entry widgets are empty. I put a label l1 on the window when empty entry fields are given. Now when the user clicks the button again after entering all the information I want to remove this label from the window. I've written the following code.

                l1_info = {}
                def sign_up_now():

                    global l1_info

                    l1 = Label(myFrame5, text="*Required field(s)\nempty.", font=("Helvetica 18 bold", 13),
                               padx=20, pady=4, bd=1, relief="groove", fg="#FF0000")

                    if user_password.index("end") == 0 or user_first_name.index("end") == 0 or user_last_name.index\
                            ("end") == 0:
                        l1.grid(row=8, column=0, columnspan=2, pady=5, padx=3, sticky="W")
                        l1_info = l1.grid_info()
                    else:
                        if l1_info != {}:
                            if l1_info["row"] == 8:
                                l1.destroy()
                            else:
                                print("Not present.")

l1_info is a global variable and its previous value remains every time the function is called. Although I've checked that the condition in the if condition becomes true (l1_info["row"] == 8), l1 label still isn't destroyed. Why is it not destroying?

Answer 1

Why is it not destroying?

Every time you call sign_up_now you're creating a new label. So, the first time through, if one of the fields is empty you create a label. Unless you go through the logic that causes the label to be destroyed, the label won't be destroyed. At this point you have one label.

Now, the user enters some data and clicks the button. The first thing you do is create another label. If they entered all the data, this second label is destroyed but the first one continues to exist. If they don't fulfill all of the criteria, you now have two labels. When the user clicks on the button again, you create a label and now have three. And so on.