C#将DataTable1数据插入到DataTable2中，请指点！

[小堇]

图一：
图二：
实现效果：
图三：


图二中列是根据图一中MC列内容而定，不定列。
各种朋友给点解决意见，谢谢！

[xdashewan]

先循环获得列名，再根据列名判断，插入数据行

[exception92]

百度 sqlserver 行转列

[本人QQ-554433626]

            DataTable dataTable = CreateTable();
                while (reader.Read())
                {
                    CreateDataRow(dataTable, reader);
                }
        private static DataTable CreateTable()
        {
            DataTable dataTable = new DataTable("dataTable");
            dataTable.Columns.Add("年份", typeof(string));
            dataTable.Columns.Add("年份", typeof(string));
            dataTable.Columns.Add("年份", typeof(string));
            return dataTable;
        }
        private static void CreateDataRow(DataTable dataTable, IDataReader reader)
        {
            DataRow dataRow = dataTable.NewRow();
            dataRow["年份"] = reader["PurchaseOrderNo"].ToString();
            dataRow["年份"] = reader["PurchaseOrderNo"].ToString();
            dataRow["年份"] = reader["PurchaseName"].ToString();
            dataTable.Rows.Add(dataRow);
        }

[本人QQ-554433626]

table转table可以把

               while (reader.Read())
                {
                    CreateDataRow(dataTable, reader);
                }

换为

            foreach (var item in oldDataTable.Rows)
            {
                
            }

[本人QQ-554433626]

DataTable dataTable = CreateTable();
            foreach (DataRow item in dataTable.Rows)
            {
                CreateDataRow(dataTable, item);
            }
       private static void CreateDataRow(DataTable dataTable, DataRow item)
        {
            DataRow dataRow = dataTable.NewRow();
            dataRow["年份"] = item["PurchaseOrderNo"].ToString();
            dataRow["年份"] = item["PurchaseOrderNo"].ToString();
            dataRow["年份"] = item["PurchaseName"].ToString();
            dataTable.Rows.Add(dataRow);
        }
        private static DataTable CreateTable()
        {
            DataTable dataTable = new DataTable("dataTable");
            dataTable.Columns.Add("年份", typeof(string));
            dataTable.Columns.Add("年份", typeof(string));
            dataTable.Columns.Add("年份", typeof(string));
            return dataTable;
        }

[guanyinsishengzi]

最好在从数据库取得时候处理

代码用linq也很简单

//行转列
            DataTable dataTable2 = new DataTable();
            dataTable2.Columns.Add("年份");
            DataColumn[] dataColumns = dataTable1.AsEnumerable().GroupBy(row => row["MC"]).Select(keyValue => new DataColumn(keyValue.Key.ToString())).ToArray();
            dataTable2.Columns.AddRange(dataColumns);

//数据插入
            var dates = dataTable1.AsEnumerable().GroupBy(row => row["JHND"]).ToArray();
            foreach (var date in dates)
            {
                DataRow dataRow = dataTable2.NewRow();
                dataRow["年份"] = date.Key.ToString();
                foreach (DataColumn column in dataColumns.Where(column => column.ColumnName != "年份"))
                {
                    dataRow[column] = dataTable1.AsEnumerable().Where(row =>
                                    row["JHND"].ToString() == date.Key.ToString() &&
                                    row["MC"].ToString() == column.ColumnName)
                            .Sum(row => Convert.ToDecimal(row["JE"]));
                }
                dataTable2.Rows.Add(dataRow);
            }

[guanyinsishengzi]

效果就这样。