DataTable的几个函数

1、调整DataTable列的顺序

dt.Columns[1].SetOrdinal(0); //将第1列改成第0列

2、复制DataRow

使用Add方法复制DataRow时会遇到该行已属于另一个表，用ImportRow就可以了。

dt.ImportRow(row);

3、行列倒置函数

        public static DataTable ColumnToRow(DataTable src_dt, int columnIndex) //columnIndex 用来当作新列名的列
        {
            DataTable dt = new DataTable();
            dt.Columns.Add(src_dt.Columns[columnIndex].ColumnName);
            List<string> lstColumnName = new List<string>();
            foreach (DataRow dr in src_dt.Rows)
            {
                if (lstColumnName.Contains(dr[columnIndex].ToString())) continue;
                if (dr[columnIndex].ToString() == string.Empty) continue;
                lstColumnName.Add(dr[columnIndex].ToString());
                dt.Columns.Add(dr[columnIndex].ToString());
            }

            int n = src_dt.Columns.Count;
            for (int i = 0; i < n; i++)
            {
                if (i == columnIndex) continue; //如果是被当作列名的列,则跳过

                DataRow new_dr = dt.NewRow();
                string columnName = src_dt.Columns[i].ColumnName;
                new_dr[0] = columnName;

                foreach (DataRow dr in src_dt.Rows)
                {
                    if (dr[columnIndex].ToString() == string.Empty) continue;
                    string newColumnName = dr[columnIndex].ToString();
                    new_dr[newColumnName] = dr[columnName];
                }

                dt.Rows.Add(new_dr);
            }
            return dt;
        }