C#调用其他方法内的函数

Question

有如下一段代码，我该如何在其他的方法里调用receivedString这个函数

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.IO.Ports;
using System.Linq;
using System.Net;
using System.Net.NetworkInformation;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static System.Windows.Forms.VisualStyles.VisualStyleElement;
using static System.Windows.Forms.VisualStyles.VisualStyleElement.ToolBar;

namespace xiaoniu
{
    public partial class Form1 : Form
    {   // 声明一个byte数组，用于存储接收到的数据
        byte[] receiveBuffer = new byte[10];
        // 声明一个变量，用于记录已经接收的数据字节数
        int receivedBytes = 0;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)   // 主窗口

        {
            //获取电脑当前可用串口并添加到选项列表中
            ComboBox1.Items.AddRange(System.IO.Ports.SerialPort.GetPortNames());
            SerialPort1.DataReceived += new SerialDataReceivedEventHandler(SerialPort1_DataReceived);
        }


        private void Button1_Click(object sender, EventArgs e)   //点击打开串口
        {
            try
            {
                if (SerialPort1.IsOpen)
                {
                    SerialPort1.Close();
                    Button1.Text = "点击打开串口";
                }
                else
                {
                    SerialPort1.PortName = ComboBox1.Text;
                    SerialPort1.Open();
                    Button1.Text = "点击关闭串口";
                }
            }
            catch (Exception ex)
            {
                //捕获可能发生的异常并进行处理

                //捕获到异常，创建一个新的对象，之前的不可以再用
                SerialPort1 = new System.IO.Ports.SerialPort();
                //刷新COM口选项
                ComboBox1.Items.Clear();
                ComboBox1.Items.AddRange(System.IO.Ports.SerialPort.GetPortNames());
                //响铃并显示异常给用户
                System.Media.SystemSounds.Beep.Play();
                Button1.Text = "打开串口";
                Button1.BackColor = Color.ForestGreen;
                MessageBox.Show(ex.Message);
            }
        }
        private void Button4_Click(object sender, EventArgs e)  //全选所有功能
        {
            RadioButton5.Checked = true;
            checkBox1.Checked = true;
            checkBox2.Checked = true;
        }

        private void RadioButton5_CheckedChanged(object sender, EventArgs e)  //控制器类
        {

        }

        private void SerialPort1_DataReceived(object sender, SerialDataReceivedEventArgs e)  //串口类
        {   // 检查是否允许跨线程调用控件，这里为了简化代码直接禁用了该功能
            CheckForIllegalCrossThreadCalls = false;
            // 读取所有可用字节数
            int bytesToRead = SerialPort1.BytesToRead;
            // 如果缓冲区大小不足以存储所有的字节，则扩展缓冲区
            if (receivedBytes + bytesToRead > receiveBuffer.Length)
            {   
                Array.Resize(ref receiveBuffer, receivedBytes + bytesToRead);
            }

            // 将所有可用字节读取到缓冲区中
            SerialPort1.Read(receiveBuffer, receivedBytes, bytesToRead);

            // 更新已经接收的字节数
            receivedBytes += bytesToRead;
            // 如果已经接收到了所有数据，则进行处理
            if (receivedBytes == receiveBuffer.Length)
            {
                // 将接收到的数据转换为十六进制字符串
                string receivedString = BitConverter.ToString(receiveBuffer).Replace("-", "");
                // 将接收到的数据显示到文本框中
                //textBox1.AppendText(receivedString + " ");

                // 将接收到的数据写入到文件中
                using (StreamWriter sw = new StreamWriter(@"C:\Users\g'x'r\Desktop\jieshou.txt", true))
                {
                    sw.Write(receivedString + " ");
                }
                
                // 清空接收缓冲区和已接收的字节数
                receivedBytes = 0;
                Array.Clear(receiveBuffer, 0, receiveBuffer.Length);
            }

        }
    }
    
}

Answer 1

1.方法和函数是一个东西，不存在方法内的函数
2.receivedString这是个字符串呀，字符串只能赋值取值，什么叫调用？
3.如果你是想在其他方法内取这个值，那你把它定义成全局变量啊，局部变量肯定没法访问