Question

我有一个DataTable，它已被转换到日期列，现在看起来像这样

+--------+------------+-------------+
|        | 1/1/2015   |  1/2/2015   |
+--------+-------+------------------+
| FieldA | Type       | MySQL       |
| FieldB | Header     | Spreads     |
| FieldC | Auto Align | On          |
+---+------------+------------------+

我希望能够做的是根据列名和行名获取特定值。因此，例如，如果我知道我希望FieldA的日期为2015年1月1日，我应该返回Type

用于转置DataTable的代码

 public static DataTable Transpose(DataTable dt)
        {
            DataTable dtNew = new DataTable();

            //adding columns    
            for (int i = 0; i <= dt.Rows.Count; i++)
            {
                dtNew.Columns.Add(i.ToString());
            }



            //Changing Column Captions: 
            dtNew.Columns[0].ColumnName = " ";

            for (int i = 0; i < dt.Rows.Count; i++)
            {
                //For dateTime columns use like below
                dtNew.Columns[i + 1].ColumnName = Convert.ToDateTime(dt.Rows[i].ItemArray[0].ToString()).ToString("MM/dd/yyyy");
                //Else just assign the ItermArry[0] to the columnName prooperty
            }

            //Adding Row Data
            for (int k = 1; k < dt.Columns.Count; k++)
            {
                DataRow r = dtNew.NewRow();
                r[0] = dt.Columns[k].ToString();
                for (int j = 1; j <= dt.Rows.Count; j++)
                    r[j] = dt.Rows[j - 1][k];
                dtNew.Rows.Add(r);
            }

            return dtNew;
        }

Answer 1

您应该能够正常访问转置的DataTable。

var monthCol = "01/01/2015"; // based on format in your code
var fieldName = "FieldA";
var res = dtTransposed.Select($"[ ] = {fieldName}")[0][monthCol]; // you really should name the first column, say "Field"

如果您知道数据的数据类型，则可以改为使用Field<>(monthCol)。

您也可以使用LINQ：

var res = dtTransposed.AsEnumerable().Where(dr => dr[" "] == fieldName).Select(dr => dr[monthCol]);

在DataTable中查找被转置的行

1 个答案: