将 Tkinter 变量从一个 function 传递到另一个

Question

I am having difficulty figuring out how to pass a variable from one class to another. In my code I have a function which holds the primary key for a database item. I would like to pass that variable into a separate class for use but I can not figure out how. The variable is names classID and I would like to pass that into the class 'class_menu'. Any help is very appreciated.

Here is my code:

class class_search_2(tk.Frame):
    def __init__(self,parent,controller):
        self.controller = controller
        tk.Frame.__init__(self,parent)
        lbl = ttk.Label(self,text="Class Search",font=("Arial",20)).pack()
        lbl2 = ttk.Label(self,text="Class Name").place(rely=0.3,relx =0.25,x=0,y=0)
        lbl3 = ttk.Label(self,text="Class Year").place(rely=0.4,relx =0.25,x=0,y=0)

        self.box1 = ttk.Entry(self,width="25")
        self.box2 = ttk.Entry(self,width="25")

        btn1 = ttk.Button(self, text="Search",width="15",
                          command= self.search_2)
        btn2 = ttk.Button(self,text="Back To Menu",width="15",
                         command=lambda: controller.show_frame(menu_2))

        btn1.place(rely=0.8,relx =0.5,x=0,y=0,anchor="center")
        btn2.place(rely=0.94,relx =0.85,x=0,y=0,anchor="center")
        self.box1.place(rely=0.3,relx =0.52,x=0,y=0)
        self.box2.place(rely=0.4,relx =0.52,x=0,y=0)

    def search_2(self):
        classname = self.box1.get()
        classyear = self.box2.get()
        find_class = ('''SELECT * FROM classes WHERE classname = ? AND classyear = ?''')
        cursor.execute(find_class,[(classname),(classyear)])
        results = cursor.fetchall()
        for row in results:##Fetches the first row of the column being classID and saves in a variable
            self.classID = (row[0])
        if results:
            self.controller.show_frame(class_menu)
            self.box1.delete(0, 'end') 
            self.box2.delete(0, 'end')
        else:
            messagebox.showerror("Error","No class found in Database")
##Function works same as login. Fetches two variables and matcbes against db. If match is found
##then loads up the classes students. If not an error message appears.

class class_menu(tk.Frame):
    def __init__(self,parent,controller):
        tk.Frame.__init__(self,parent)
        lbl = ttk.Label(self,text="Class Menu (Admin)",font=("Arial",20)).pack()
        btn1 = ttk.Button(self, text="Remove Class",width="15",)
        btn2 = ttk.Button(self, text="Display Students",width="15")
        btn3 = ttk.Button(self, text="Add Students",width="15") 
        btn4 = ttk.Button(self,text="Back To Menu",width="15",
                         command=lambda: controller.show_frame(menu_2))

        btn1.place(rely=0.435,relx =0.5,x=0,y=0,anchor="center")
        btn2.place(rely=0.550,relx =0.5,x=0,y=0,anchor="center")
        btn3.place(rely=0.675,relx =0.5,x=0,y=0,anchor="center")
        btn4.place(rely=0.94,relx =0.85,x=0,y=0,anchor="center")

Answer 1

class class_search_2():
    def __init__(self):
        self.classID = None

    def search_2(self):
            self.classID = 5  # I assumed that


class class_menu():
    def __init__(self, classID):
        self.classID = classID

    def print_classID_in_class_menu(self):
        print(self.classID)


obj1 = class_search_2()
obj1.search_2()
print("ClassID is ", obj1.classID)

obj2 = class_menu(obj1.classID)
obj2.print_classID_in_class_menu()

I simplified the problem. You can create an object and, pass classID value to another class using this object attirubute.