跨线程操作无效Datagridview c＃

Question

在c＃中使用Backgroundworker时，我遇到了跨线程操作错误。

private void IndexForm_Load(object sender, EventArgs e)
    {
        BG.RunWorkerAsync();
    }

private void BG_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        List<int> _i = new List<int>();
        _i.Add(2);
        dataGridView1.DataSource = _i;
    }

如果我填充Combobox就好了。例如

RunWorkerCompletedEventArgs e)
    {
        List<int> _i = new List<int>();
        _i.Add(2);
        comboBox1.DataSource = _i;
    }

无法理解原因。