关于ComboBox线程报错问题,求解。解答有效5VX

private void ProcessVpp(object ob)
{

        while (true)
        {


            if (_threadStart.WaitOne())
            {


                if (_SN_Check_Enable)//查询PDCA的操作员和SN是否存在
                {
                    
                   if (cmbbox_Language_Changer.Text == "Chinese")   **//线程报错*__*

                    {
                        //查询PDCA的操作员和SN是否存在
                        if (_sn == string.Empty)
                        {
                            _frmDisplay.RecordInformation2("产品信息缺失", Color.Red);
                            continue;
                        }
                        else
                        {

                            if (_PDCACheckResult)
                            {
                                _frmDisplay.RecordInformation2("产品信息OK", Color.Green);
                            }

                        }
                    }
                    else if (cmbbox_Language_Changer.Text == "English")
                    {
                        //查询PDCA的操作员和SN是否存在
                        if (_sn == string.Empty)
                        {
                            _frmDisplay.RecordInformation2("Missing product information", Color.Red);
                            continue;
                        }
                        else
                        {

                            if (_PDCACheckResult)
                            {
                                _frmDisplay.RecordInformation2("Product Information OK", Color.Green);
                            }

                        }
                    }
                    else if (cmbbox_Language_Changer.Text == "Việt nam")
                    {
                        //查询PDCA的操作员和SN是否存在
                        if (_sn == string.Empty)
                        {
                            _frmDisplay.RecordInformation2("hông tin sản phẩm bị mất", Color.Red);
                            continue;
                        }
                        else
                        {

                            if (_PDCACheckResult)
                            {
                                _frmDisplay.RecordInformation2("Thông tin sản phẩm OK", Color.Green);
                            }

                        }
                    }

                }

}