Question

一、数据记录

 EnumerableRowCollection<DataRow> query 
    = from order in _table.AsEnumerable()
      where order.Field<Int32>("key") > 2 && order.Field<Int32>("key") < 4
      select order.Field<Int32>("key")=1000, order.Field<string>("name");

我可以这样说。

审判

select new {key= 1000,name= order.Field<string>("name") };

i got

    Cannot implicitly convert type 
    System.Data.EnumerableRowCollection<AnonymousType#1>    
    to  System.Data.EnumerableRowCollection<System.Data.DataRow>

如何形成权利问题? 我的任务是用1 000个钥匙取代钥匙,并按现在的名称删除。

Answer 1

When you write select new {key= 1000,name= order.Field<string>("name") }, you re creating a new anonymous type that has nothing to do with DataRow.
Therefore, you can t assign it to a EnumerableRowCollection<DataRow>.

为确定汇编错误,修改<代码> EmathableRowCollection<DataRow> to var。





However, that won t fix your underlying problem.

LINQ cannot be used to modify data.

您需要使用正常的<代码>foreach loop,并确定key。 价值观,如:

var affectedRows = from order in _table.AsEnumerable()
  where order.Field<Int32>("key") > 2 && order.Field<Int32>("key") < 4
  select row;
foreach(DataRow row in affectedRows) {
    row["key"] = 1000;
}


This code will modify the original DataRows in the original _table.

If you don t want to modify the original _table, you can copy it by calling DataTable.Copy().

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