使用python tkinter编写一个可以选择串口，打开串口、关闭串口的串口助手

好的，以下是一个简单的串口助手程序示例，可以选择串口、打开和关闭串口：

import serial
import tkinter as tk
from tkinter import ttk

class SerialAssistant:
    def __init__(self, root):
        self.root = root
        self.ser = None
        self.frame = ttk.Frame(root, padding="3 3 12 12")
        self.frame.grid(column=0, row=0, sticky=(tk.N, tk.W, tk.E, tk.S))
        self.frame.columnconfigure(0, weight=1)
        self.frame.rowconfigure(0, weight=1)

        self.port_var = tk.StringVar()
        self.port_var.set("COM1")
        self.baud_var = tk.StringVar()
        self.baud_var.set("9600")
        self.status_var = tk.StringVar()
        self.status_var.set("Disconnected")

        ttk.Label(self.frame, text="Port:").grid(column=1, row=1, sticky=tk.W)
        self.port_combo = ttk.Combobox(self.frame, width=10, textvariable=self.port_var)
        self.port_combo.grid(column=2, row=1, sticky=(tk.W, tk.E))
        self.port_combo['values'] = tuple(["COM{}".format(i) for i in range(1, 21)])
        self.port_combo.current(0)

        ttk.Label(self.frame, text="Baud rate:").grid(column=1, row=2, sticky=tk.W)
        self.baud_entry = ttk.Entry(self.frame, width=10, textvariable=self.baud_var)
        self.baud_entry.grid(column=2, row=2, sticky=(tk.W, tk.E))
        self.baud_entry.focus()

        self.status_label = ttk.Label(self.frame, textvariable=self.status_var)
        self.status_label.grid(column=1, row=3, columnspan=2, sticky=tk.W)

        self.connect_button = ttk.Button(self.frame, text="Connect", command=self.connect)
        self.connect_button.grid(column=1, row=4, sticky=tk.W)
        self.disconnect_button = ttk.Button(self.frame, text="Disconnect", command=self.disconnect, state="disabled")
        self.disconnect_button.grid(column=2, row=4, sticky=tk.E)

        ttk.Separator(self.frame, orient="horizontal").grid(column=1, row=5, columnspan=2, sticky=(tk.W, tk.E))

        self.send_label = ttk.Label(self.frame, text="Send:")
        self.send_label.grid(column=1, row=6, sticky=tk.W)
        self.send_entry = ttk.Entry(self.frame, width=30)
        self.send_entry.grid(column=2, row=6, sticky=(tk.W, tk.E))
        self.send_entry.bind("<Return>", self.send)

        ttk.Separator(self.frame, orient="horizontal").grid(column=1, row=7, columnspan=2, sticky=(tk.W, tk.E))

        self.receive_label = ttk.Label(self.frame, text="Receive:")
        self.receive_label.grid(column=1, row=8, sticky=tk.W)
        self.receive_text = tk.Text(self.frame, width=30, height=10)
        self.receive_text.grid(column=2, row=8, sticky=(tk.W, tk.E))

    def connect(self):
        try:
            self.ser = serial.Serial(self.port_var.get(), int(self.baud_var.get()), timeout=1)
            self.status_var.set("Connected")
            self.connect_button.config(state="disabled")
            self.disconnect_button.config(state="enabled")
        except serial.SerialException:
            self.status_var.set("Connection failed")

    def disconnect(self):
        if self.ser:
            self.ser.close()
            self.ser = None
        self.status_var.set("Disconnected")
        self.connect_button.config(state="enabled")
        self.disconnect_button.config(state="disabled")

    def send(self, event):
        if self.ser:
            data = self.send_entry.get()
            self.ser.write(data.encode())
            self.send_entry.delete(0, tk.END)
            self.receive_text.insert(tk.END, "> {}\n".format(data))

if __name__ == "__main__":
    root = tk.Tk()
    root.title("Serial Assistant")
    SerialAssistant(root)
    root.mainloop()

运行上述代码，即可打开一个简单的串口助手界面，可以选择串口，打开和关闭串口，发送和接收数据。