LINQ查询数据表 [英] LINQ query on a DataTable
问题描述
我试图在DataTable对象上执行LINQ查询,而且我发现在DataTable上执行这样的查询并不简单。例如:
I'm trying to perform a LINQ query on a DataTable object and bizarrely I am finding that performing such queries on DataTables is not straightforward. For example:
var results = from myRow in myDataTable
where results.Field("RowNo") == 1
select results;
这是不允许的。我如何得到这样的工作?
This is not allowed. How do I get something like this working?
我很惊讶,数据表不允许LINQ查询!
I'm amazed that LINQ queries are not allowed on DataTables!
推荐答案
您不能查询 DataTable
的行集合,因为 DataRowCollection
不实现 IEnumerable< T>
。您需要为 DataTable
使用 AsEnumerable()
扩展名。像这样:
You can't query against the DataTable
's Rows collection, since DataRowCollection
doesn't implement IEnumerable<T>
. You need to use the AsEnumerable()
extension for DataTable
. Like so:
var results = from myRow in myDataTable.AsEnumerable()
where myRow.Field<int>("RowNo") == 1
select myRow;
正如Keith所说,您需要添加对 System.Data.DataSetExtensions
And as Keith says, you'll need to add a reference to System.Data.DataSetExtensions
AsEnumerable()
返回 IEnumerable< DataRow>
。如果您需要将 IEnumerable< DataRow>
转换为 DataTable
,请使用 CopyToDataTable()
扩展名。
AsEnumerable()
returns IEnumerable<DataRow>
. If you need to convert IEnumerable<DataRow>
to a DataTable
, use the CopyToDataTable()
extension.
这篇关于LINQ查询数据表的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!