C# 多线程更新界面的错误的解决方法

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var thread2 = new System.Threading.Thread(WriteTextUnsafe);
            thread2.Start();
        }

        private void WriteTextUnsafe() =>
            textBox1.Text = "This text was set unsafely.";
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            var threadParameters = new System.Threading.ThreadStart(
                delegate { WriteTextSafe("This text was set safely."); });
            var thread2 = new System.Threading.Thread(threadParameters);
            thread2.Start();
        }

        public void WriteTextSafe(string text)
        {
            if (textBox1.InvokeRequired)
            {
                // Call this same method but append THREAD2 to the text
                Action safeWrite = delegate { WriteTextSafe($"{text} (THREAD2)"); };
                textBox1.Invoke(safeWrite);
            }
            else
                textBox1.Text = text;
        }
    }
}