怎么防止下拉列表控件的EditvalueChanged事件進入死循環

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當 下拉列表控件選中后判定另一個為空，return之前需要將該下拉列表清空，就又會觸發Changed事件，解決方案就是將空值的判斷放置最外層，代碼如下：

 private void gluCOATemplate_EditValueChanged(object sender, EventArgs e)
        {
            try
            {
                if (gluCOATemplate.Text != "")
                {
                    string sCoaId = gluCOATemplate.Text;
                    string sBacthId = txtLotID.Text;
                    if (txtLotID.Text == "")
                    {
                        CommonFunction.ShowMsgBox("檢查批號不能為空");
                        InitgdvCoaItem();
                        gluCOATemplate.Text = "";
                        txtLotID.Focus();
                        return;
                    }
                    if (gluCOATemplate.Text == "")
                    {
                        CommonFunction.ShowMsgBox("請選擇模板ID");
                        gluCOATemplate.Focus();
                        return;
                    }

                    if (txtLotID.Text != "" && sCoaId != "")
                    {
                        DataTable dt = new DataTable();
                        dt = QCMLIST.QCM_View_COA_Detail(sCoaId, sBacthId);

                        if (dt != null)
                        {
                            udcGVNewDelCtrl1.RecordCount = dt.Rows.Count;
                            //DevGridControlHelper.BindData(gdcCOAItem, dt);
                            DevGridControlHelper.BindData(gdcCOAItem, dt, new int[] { 1, 1, 1, 1, 1, 1 });
                        }
                        else
                        {
                            InitgdvCoaItem();
                        }

                    }
                }
            }
            catch (Exception ex)
            {
                CommonFunction.ShowMsgBox(ex.Message);
                return;
            }
        }

===============

防止添加的數據主鍵沖突：

一開始沒有主鍵就取查到的最大值+1，

int iSeq = InTag.coa_list[i].item_seq;
                            if (iSeq == 0)//傳入的Seq為空（0）時，取數據庫中最大的+1，否則直接保存
                            {
                                List<UQcmcoaitem> uQcmcoaitemlist = ctx.UQcmcoaitem.Where(t => t.PkgNoticeNo == sPkgId && t.Factory == sFactory).OrderByDescending(t=>t.ItemSeq).ToList();
                                if (uQcmcoaitemlist != null)
                                {
                                    iSeq = uQcmcoaitemlist[0].ItemSeq + 1;
                                }
                                else
                                {
                                    iSeq = 1;
                                }
                            }
                            UQcmcoaitem uQcmcoaItem = new UQcmcoaitem
                            {
                                PkgNoticeNo = sPkgId,
                                Factory = sFactory,
                                ItemSeq = iSeq,
                                TestingResult =InTag.coa_list[i].testing_result,

                                TestingItem = InTag.coa_list[i].testing_item,
                                TestingSpec = InTag.coa_list[i].testing_specification,
                                TestingMethod = InTag.coa_list[i].testing_method,
                                Dimens = InTag.coa_list[i].dimens,
                                CreateTime = DBGV._dbc.DB_GetSysTime(),
                                CreateUserId = InTag._cmn_in._user_id
                            };
                            ctx.UQcmcoaitem.Add(uQcmcoaItem);

但是當添加多條Seq=0的數據時，從數據庫查出的最大值+1就會使得要添加的這幾天數據的主鍵沖突，因為事務還沒提交，Seq都是Max+1

解決方法：在循環外面加一個int變量（count=0），每次Max+1后，再加上count：

 int count = 0;
for (int i = 0; i < InTag.coa_list.Length; i++)
{
                      if (InTag.coa_list[i].step == 'I')
                        {
                            int iSeq = InTag.coa_list[i].item_seq;
                            if (iSeq == 0)
                            {
                                List<UQcmcoaitem> uQcmcoaitemlist = ctx.UQcmcoaitem.Where(t => t.PkgNoticeNo == sPkgId && t.Factory == sFactory).OrderByDescending(t=>t.ItemSeq).ToList();
                                if (uQcmcoaitemlist != null)
                                {
                                    iSeq = uQcmcoaitemlist[0].ItemSeq + 1+count;
                                    count++;
                                }
                                else
                                {
                                    iSeq = 1;
                                }
                            }
                            UQcmcoaitem uQcmcoaItem = new UQcmcoaitem
                            {
                                PkgNoticeNo = sPkgId,
                                Factory = sFactory,
                                ItemSeq = iSeq,
                                TestingResult =InTag.coa_list[i].testing_result,

                                TestingItem = InTag.coa_list[i].testing_item,
                                TestingSpec = InTag.coa_list[i].testing_specification,
                                TestingMethod = InTag.coa_list[i].testing_method,
                                Dimens = InTag.coa_list[i].dimens,
                                CreateTime = DBGV._dbc.DB_GetSysTime(),
                                CreateUserId = InTag._cmn_in._user_id
                            };
                            ctx.UQcmcoaitem.Add(uQcmcoaItem);
                        }
                        else
                        {
                            sMsgCode = "QCM-0004";
                            return GlobalConstant.FAIL;
                        }
                    }
                    ctx.SaveChanges();
                    transaction.Commit();

GridLookUpEdit下拉列表的高度設置：

將properties中的AutoHeight設置為false，再設置size的值

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