如何将两个DataTable与普通值进行比较 [英] How to compare two DataTables with common values
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问题描述
我有两个datatable dt1和st2。
I have two datatable dt1 and st2.
dt1由 PorductId
ProductName
FilePath
:
1 Product1 c:\
2 Product2 c:\
3 Product3 c:\
4 Product4 c:\
dt2由 ProductName
DateofDelivery
:
Product2 2016-01-03
Product3 2016-03-02
Product5 2016-02-03
Product7 2014-09-01
我需要返回dt2中dt2的ProductName的所有行,应该是:
I need to return all rows from dt2 where the ProductName of dt2 is in dt1 the result should be:
Product2 2016-01-03
Product3 2016-03-02
我已经尝试过这个,但它不工作:
I've tried this, but its not working:
var matched = from table1 in dt1.AsEnumerable()
join table2 in dt2.AsEnumerable()
on table1.Field<string>("ProductName") equals table2.Field<string>("ProductName")
推荐答案
是第一个过滤第二个Datatable,我会使用一个而不是一个连接,下面的示例应该复制你想要做的:
Really what you want to do is filter the second Datatable by the first, I would use a where instead of a join, the example below should replicate what your trying to do:
//Assemble the DataTables mentioned in your question
DataTable dt1 = new DataTable();
dt1.Columns.Add("ID", typeof(int));
dt1.Columns.Add("ProductName", typeof(string));
dt1.Columns.Add("Path", typeof(string));
dt1.Rows.Add(1, "Product1", "c:\\");
dt1.Rows.Add(2, "Product2", "c:\\");
dt1.Rows.Add(3, "Product3", "c:\\");
dt1.Rows.Add(4, "Product4", "c:\\");
DataTable dt2 = new DataTable();
dt2.Columns.Add("ProductName", typeof(string));
dt2.Columns.Add("Date", typeof(string));
dt2.Rows.Add("Product2", "2016-01-03");
dt2.Rows.Add("Product3", "2016-01-04");
dt2.Rows.Add("Product5", "2016-01-05");
dt2.Rows.Add("Product7", "2016-01-06");
//Get the values from dt1 to filter by
var filter = dt1.AsEnumerable().Select(b => b.Field<string>("ProductName")).ToList();
//Then filter the second list by the ProductName of the first list
var matched = dt2.AsEnumerable().Where(a => filter.Contains(a.Field<string>("ProductName")))
.ToList();
希望有帮助
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