我找不到以下問題的解決方案。a給定的是一個(gè)帶有 4 個(gè)入口小部件, b, c,的 tkinter 應(yīng)用程序，d它必須滿足以下條件：條目中只能輸入數(shù)字a，且不得超過 4 位數(shù)字如果a為空則無法在 中進(jìn)行輸入c。c和的內(nèi)容d與 相同b。如果a不為空，則可以在 中進(jìn)行輸入c。c和的內(nèi)容d相同（它們與 未鏈接b）。當(dāng)前的解決方案僅部分起作用。它能夠鏈接條目b和c取消鏈接它們。但我不知道如何包含 3 條件。from tkinter import *root = Tk()root.geometry("200x200")def only_numeric_input(P):    if len(P) > 0 and P.isdigit():        # enable entry_c and unlink its content from entry_b        entry_c.config(textvariable=" ", state='normal')    else:        # disable entry_c        entry_c.config(textvariable=var_b, state='disabled')    if len(P) > 4:        return False    # checks if entry's value is an integer or empty and returns an appropriate boolean    if P.isdigit() or P == "":  # if a digit was entered or nothing was entered        return True    return Falsecallback = root.register(only_numeric_input)  # registers a Tcl to Python callbackvar_b = StringVar()var_c = StringVar()Label(root, text="a").grid(row = 0, column = 0, pady = (10,0))Label(root, text="b").grid(row = 1, column = 0)Label(root, text="c").grid(row = 2, column = 0)Label(root, text="d").grid(row = 3, column = 0, pady = (40,0))entry_a = Entry(root)entry_b = Entry(root, textvariable = var_b)entry_c = Entry(root, textvariable = var_b, state = "disabled")entry_d = Entry(root, textvariable = var_b)#display entrysentry_a.grid(row = 0, column = 1)entry_b.grid(row = 1, column = 1)entry_c.grid(row = 2, column = 1)entry_d.grid(row = 3, column = 1, pady = (40,0))entry_a.configure(validate="key", validatecommand=(callback, "%P"))  # enables validationmainloop()