C# 下划线转驼峰

/// <summary>
/// 转换
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_Click(object sender, EventArgs e)
{
    string tb1 = textBox1.Text;
    Match mt = Regex.Match(tb1, @"_(\w*)*");
    while (mt.Success)
    {
        var item = mt.Value;
        while (item.IndexOf('_') >= 0)
        {
            string newUpper = item.Substring(item.IndexOf('_'), 2);
            item = item.Replace(newUpper, newUpper.Trim('_').ToUpper());
            tb1 = tb1.Replace(newUpper, newUpper.Trim('_').ToUpper());
        }
        mt = mt.NextMatch();
    }

    textBox2.Text = tb1;
}