求教提示(指定的转换无效)怎么解决

Question

本帖最后由 mingjie_520 于 2010-10-29 13:31:55 编辑

Answer 1

comPort_DataReceived中的代码是什么？

Answer 2

try
            {
                string str = comPort.ReadExisting();
                string strSql = "";
                dtRs = null;
                this.SQLQueryDB(strSql, ref dtRs);
                if (dtRs.Rows.Count > 0)
                {                    //}                    
                }
                else
                {
                    //strSql = 
                    strSql = 
                    dtRs = null;
                    this.SQLQueryDB(strSql, ref dtRs);
                    if (dtRs.Rows.Count >0)
                    {
                        //strSql =""                        strSql = 
                        this.SQLQueryDB(strSql, ref dtRs1);
                        if (dtRs1.Rows .Count>0)
                        {
                            TimeSpan t=DateTime.Now.TimeOfDay.Subtract(Convert.ToDateTime(dtRs.Rows[0]["进厂时间"]).TimeOfDay);
                            if (t.Hours>=Convert.ToInt32(dtRs1.Rows[0]["间隔时间"]))
                            {
                                strSql =
                                this.SQLWork(strSql);
                                this.SQLWork(strSql);                                this.SQLWork(strSql);
                                this.SQLWork(strSql);   
                                this.DBServerQuery(strSql, ref dtRs2);
                                for (int ii = 0; ii < dtRs2.Rows.Count;ii++ )
                                {
     
                                    this.DBServerWork(strSql);
                                }
                            }
                        }
                    }

Answer 3

 private void comPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
            
            DataTable dtRs = null;
            DataTable dtRs1 = null;
            DataTable dtRs2 = null;
            
            try
            {
                string str = comPort.ReadExisting();
                string strSql = "
                dtRs = null;
                this.SQLQueryDB(strSql, ref dtRs);
                if (dtRs.Rows.Count > 0)
                {
                    strSql = "";
                    this.SQLWork(strSql);                    //strSql = "";
                    //this.SQLQueryDB(strSql, ref dtRs2);
                    //if (dtRs2.Rows.Count == 0)
                    //{
                        strSql = "";
                        this.SQLWork(strSql);
                    //}                    
                }
                else
                {
                    //strSql = "";
                    strSql = "";
                    dtRs = null;
                    this.SQLQueryDB(strSql, ref dtRs);
                    if (dtRs.Rows.Count >0)
                    {
                        //strSql =""                        strSql = "";
                        this.SQLQueryDB(strSql, ref dtRs1);
                        if (dtRs1.Rows .Count>0)
                        {
                            TimeSpan t=DateTime.Now.TimeOfDay.Subtract(Convert.ToDateTime(dtRs.Rows[0]["进厂时间"]).TimeOfDay);
                            if (t.Hours>=Convert.ToInt32(dtRs1.Rows[0]["间隔时间"]))
                            {
                                strSql ="";
                                this.SQLWork(strSql);
                                this.SQLWork(strSql);                                strSql = "";
                                this.SQLWork(strSql);
                                this.SQLWork(strSql);                                strSql = "";
                                this.DBServerQuery(strSql, ref dtRs2);
                                for (int ii = 0; ii < dtRs2.Rows.Count;ii++ )
                                {
                                    strSql = "";
                                    this.DBServerWork(strSql);
                                }
                            }
                        }
                    }
                    else
                    {                        string strInto = "请注意该车不能进厂！";
                        SpeechLib.SpeechVoiceSpeakFlags SpFlags = SpeechLib.SpeechVoiceSpeakFlags.SVSFDefault;
                        SpeechLib.SpVoice Voice = new SpeechLib.SpVoice();
                        Voice.Voice = Voice.GetVoices(string.Empty, string.Empty).Item(0);
                        Voice.Speak(strInto, SpFlags);                    }
                }            }
            catch (System.Exception ex)
            {
                this.MsgBoxShow(ex.ToString());
            }
        }
别看3楼的是这段

Answer 4

可能是在SQL语句中出了问题，比如 ...where a=12345 而你数据库里的字段是字符型的
你最好是把异常堆栈贴出来，否则很难定位

Answer 5

自己解决，串口组件COM是多线程，要用委托来解决