Вывод строк в combobox

Столкнулся с проблемой с combobox, не выводится строка с названием беседы ВК.

Перейду сразу к коду Form1

public partial class Form1 : Form
{
    VkApi vk = new VkApi();
    long chatid;
    long userid;
    bool _reg = false;
    public Form1(List<string> _chats)
    {
        InitializeComponent();
        if (_reg == false) Registry();
        else
        {
            for (int i = 0; i < _chats.Count; i++)
            {
                comboBox1.Items.Add(vk.Messages.GetChat(Convert.ToInt64(_chats)).Title);
            }
        }
    }
    public Form1()
    {
        InitializeComponent();
    }
    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
    }
    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        userid = Convert.ToInt32(textBox1.Text);
    }

    private void button1_Click(object sender, EventArgs e)
    {
        if (_reg == false) Registry();
        else
        {
            if (comboBox1.SelectedIndex == 0) chatid = 101;
            else if (comboBox1.SelectedIndex == 1) chatid = 86;
            else chatid = 20;
            try { vk.Messages.RemoveChatUser(chatid, userid); }
            catch
            {
                MessageBox.Show("Произошёл сбой при кике!\nПроверьте ID пользователя", "Ошибка!");
            }
        }
    }
    private void Registry()
    {
        ulong appID = appid;
        string login = "login";
        string pass = "pass";
        Settings scope = Settings.All;
        vk.Authorize(new ApiAuthParams
        {
            ApplicationId = appID,
            Login = login,
            Password = pass,
            Settings = scope,
        });
        _reg = true;
    }
    private void button2_Click(object sender, EventArgs e)
    {
        Form f2 = new Form2();
        f2.Show();
        Hide();
    }
}

Form2

VkApi vk = new VkApi();
    long chatid;
    string name;
    string directory = "E:\\Chats.txt";
    List<string> chats = new List<string>();
    public Form2()
    {
        InitializeComponent();
    }
    private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (!Char.IsDigit(e.KeyChar))
        {
            e.KeyChar = '\0';
        }
    }
    private void textBox1_TextChanged(object sender, EventArgs e)
    {
    }

    private void button1_Click(object sender, EventArgs e)
    {
        ulong appID = appid;
        string login = "login";
        string pass = "pass";
        Settings scope = Settings.All;
        vk.Authorize(new ApiAuthParams
        {
            ApplicationId = appID,
            Login = login,
            Password = pass,
            Settings = scope,
        });
        name = vk.Messages.GetChat(chatid).Title;
        MessageBox.Show(name, "test");
        TextWrite(Convert.ToInt32(textBox1.Text));
        Form f1 = new Form1(chats);
        f1.Show();
        Hide();
    }
    private void button2_Click(object sender, EventArgs e)
    {
        Form f1 = new Form1();
        f1.Show();
        Hide();
    }
    private void TextWrite(int chatid)
    {
        chats.Add(Convert.ToString(chats));
        for (int i = 0; i < chats.Count; i++)
        {
            if (File.Exists(directory)) File.WriteAllLines(directory, chats);
        }
    }