如何.GroupBy多列LINQ/Projection？

Question

如何使用linq投影按多列進行分組？

事情是這樣的：

var q = db.Areas.GroupBy(x => x.AreaCatId, x.AreaCatName, x.AreaId, x.AreaName); 

在平坦的結果得到的設置，如：

AreaCatId, AreaCatName, AreaId, AreaName 
0   US   1  FL 
0   US   2  NY 
1   Canada  3  BC 

Answer 1

可以GROUPBY匿名類型：

var q = db.Areas.GroupBy(
      x => new 
       { 
        CatId = x.AreaCatId, 
        CatName = x.AreaCatName, 
        Id = x.AreaId, 
        Name = x.AreaName 
       });