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我有两个数据表,我想和他们一起几个columns.here是我的代码如何在多个条件列上连接两个数据表?
DataTable targetTable = dtl.Clone();
var dt2Columns = dt.Columns.OfType<DataColumn>().Select(dc =>
new DataColumn(dc.ColumnName, dc.DataType, dc.Expression, dc.ColumnMapping));
targetTable.Columns.AddRange(dt2Columns.ToArray());
var rowData =
from row1 in dtl.AsEnumerable()
join row2 in dt.AsEnumerable()
on row1.Field<string>("header")
equals row2.Field<string>("header")
where (row1.Field<string>("digitnumber") != "")
select row1.ItemArray.Concat(row2.ItemArray).ToArray();
foreach (object[] values in rowData)
targetTable.Rows.Add(values);
,但它的连接只在一个condition.I要像下面的代码:
DataTable targetTable = dtl.Clone();
var dt2Columns = dt.Columns.OfType<DataColumn>().Select(dc =>
new DataColumn(dc.ColumnName, dc.DataType, dc.Expression, dc.ColumnMapping));
targetTable.Columns.AddRange(dt2Columns.ToArray());
var rowData =
from row1 in dtl.AsEnumerable()
join row2 in dt.AsEnumerable()
on row1.Field<string>("header") and row1.Field<string>("digitrow") and row1.Field<string> ("response")
equals row2.Field<string>("header") and row1.Field<string>("question") and and row1.Field<string> ("answer")
where (row1.Field<string>("digitnumber") != "")
select row1.ItemArray.Concat(row2.ItemArray).ToArray();
foreach (object[] values in rowData)
targetTable.Rows.Add(values);
但在多种情况下有一些错误。解决方法是什么?请帮助我。
[LINQ在多个条件中的On子句中加入]的可能重复(http://stackoverflow.com/questions/7664727/linq-join-with-multiple-conditions-in-on-on-clause) – PaulF