LINQ - 基于多个不同的列返回包含表的所有列的行

我有一张桌子,

**Matter No      Client No    Client Name  Invoice No  Invoice Date    Invoice Amt**

1111-0001          1111          ABC            101       01/01/2013       100.00 
1111-0001          1111          ABC            102       02/01/2013       200.00
1111-0001          1111          ABC            103       03/01/2013       300.00
1111-0001          1111          ABC            104       04/01/2013       400.00
1111-0001          1112          DEF            105       05/01/2013       500.00
1111-0001          1113          GHI            106       06/01/2013       600.00

基于上面的场景,我希望返回所有列,但DISTINCT ROWS基于Columns - Matter No和Client No.,即我需要看到3行作为输出:

**Matter No      Client No    Client Name  Invoice No  Invoice Date    Invoice Amt**

1111-0001          1111          ABC            101       01/01/2013       100.00 
1111-0001          1112          DEF            105       05/01/2013       500.00
1111-0001          1113          GHI            106       06/01/2013       600.00

我如何在LINQ中实现这一目标？

提前致谢

from x in table
group x by new {x.MatterNo, x.ClientNo}
into mygroup
select mygroup.First();

或者如果您更喜欢这种语法

list.DistinctBy(x => new {x.MatterNo, x.ClientNo});

如果您没有处理列表,可以尝试

from DataRow drow in dtable.Rows
group drow by new {MatterNo = drow["Matter No"], ClientNo = drow["Client No"]}
into myGroup
select myGroup.First();