注意：SourceDt为源表，field为去重字段（可增加）

        private DataTable GetDistinctSelf(DataTable SourceDt, string field)
        {
            int j = SourceDt.Rows.Count;
            if (j > 1)
            {
                int k = j - 2;
                int i = 1;
                while (i <= k)
                {
                    DataRow dr = SourceDt.Rows[i];
                    string isbn = dr[field].ToString();
                    DataRow[] rows = SourceDt.Select(string.Format("{0}='{1}'", field, isbn));
                    if (rows.Length > 1)
                    {
                        SourceDt.Rows.RemoveAt(i); //存在重复就移除
                        k = k - 1;
                    }
                    else
                    {
                        i++;
                    }
                }
            }
            return SourceDt;
        }

取差集

private DataTable ExcelNo()
        {
            DataTable excel = excelToDt();//读取excel的dt
            DataTable except = new DataTable(); //接受差集的dt
            DataTable dt2 = shelvesbll.isGoodsShelves(regId); //读取数据库的dt
            //接受差集dt的列名
            except.Columns.Add("id", typeof(string));
            except.Columns.Add("货架名称", typeof(string));
            except.Columns.Add("地区ID", typeof(string));

            DataRowCollection count = excel.Rows;
            foreach (DataRow row in count)//遍历excel数据集
            {
                try
                {
                    string goodsName = row[1].ToString();
                    DataRow[] rows = dt2.Select(string.Format("shelvesName='{0}'", goodsName)); //查询货架名称是否重复
                    if (rows.Length == 0)//判断如果DataRow.Length为0，即该行excel数据不存在于数据库中，就插入到差集中
                    {
                        except.Rows.Add(row[0], row[1], row[2]);
                    }
                }
                catch (Exception ex)
                {
                    Response.Write(ex);
                    Response.End();
                }
            }
            return except;
        }

原文链接：https://www.idaobin.com/archives/1969.html

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