Question

我有两个DataTable dt_original和dt_updated。我想将它们合并在一起有条件的话，只有当dt_updated与dt_orignal具有相同的item_id时，如何合并行？

dt_original： -

item_id|item_name|qty|unitprice|col1|col2|col3|
===============================================
1      |apple    |5  |1.00     |xxx |xxx |xxx |
2      |orange   |10 |2.00     |xxx |xxx |xxx |

dt_updated： -

item_id|item_name|qty|
======================
1      |apple    |2  |

我想要的结果： -

item_id|item_name|qty|unitprice|col1|col2|col3|
===============================================
1      |apple    |2  |1.00     |xxx |xxx |xxx |

mycode的：

Dim dt_original As DataTable = Model_Query(str_tableControl1)
Dim dt_result As DataTable

dt_original.PrimaryKey = New DataColumn() {dt_original.Columns("item_id")}
dt_updated.PrimaryKey = New DataColumn() {dt_updated.Columns("item_id")}
dt_original.Merge(dt_updated)
dt_result = dt_original

MyResult： -

item_id|item_name|qty|unitprice|col1|col2|col3|
===============================================
1      |apple    |2  |1.00     |xxx |xxx |xxx |
2      |orange   |10 |2.00     |xxx |xxx |xxx |

那么如何解决这个问题？

Answer 1

您想要更新数量字段吗？我会使用LINQ和循环：

Dim updatedRows = From rowOriginal In dt_original.AsEnumerable()
                  Join rowUpdated In dt_updated.AsEnumerable()
                  On rowOriginal.Field(Of Int32)("item_id") Equals rowUpdated.Field(Of Int32)("item_id")

Dim dt_result As DataTable =  dt_original.Clone() ' empty table, same columns 
For Each x In updatedRows
    dt_result.ImportRow(x.rowOriginal)
    dt_result.Rows(dt_result.Rows.Count-1).SetField("qty", x.rowUpdated.Field(of int32)("qty"))
Next

如果您想更新原始表格，那就更容易了：

For Each x In updatedRows
    x.rowOriginal.SetField("qty", x.rowUpdated.Field(of int32)("qty"))
Next

如何将两个DataTable与条件合并

1 个答案: