VB.NET查询数据表

Question

我有一个DataTable

|------------|
| id | x | y |
|------------|
|  1 | 1 | 1 |
|  2 | 1 | 2 |
|  3 | 2 | 1 |
|  4 | 2 | 2 |
|------------|

我想用x的值过滤这个DataTable来得到一个新的DataTable

if x = 1
|------------|
| id | x | y |
|------------|
|  1 | 1 | 1 |
|  2 | 1 | 2 |
|------------|

or x = 2 
|------------|
| id | x | y |
|------------|
|  3 | 2 | 1 |
|  4 | 2 | 2 |
|------------|

填充数据集和数据表的查询仍然让我感到困惑。谢谢你的帮助。

Answer 1

您首先filter the data：

MyTable.DefaultView.RowFilter = "x = 1"

然后你copy the view to a new table：

Dim MyNewTable As DataTable = Mytable.DefaultView.ToTable

Answer 2

您可以尝试创建新的DataTable并克隆原始DataTable以引入架构和约束。然后过滤行并将其添加到新的DataTable。

Dim newDT As DataTable = oldDT.Clone()

Dim filter As string = "x = 1"; 

//get the rows from the that have been filtered
DataRow[] filteredRows = oldDT.Select(filter);

//add the rows to the new datatable
For Each dr As DataRow In filteredRows
    newDT.ImportRow(dr)
Next