如何使用C＃4.0獲得Datatable與linq

Question

的總和。 我的數據表是這樣的：

ZONE Value 
A  10 
A  20 
B  5 
C  15 
C  5 

我想區的總和。

Zone A = 30 
Zone B = 5 
Zone C = 20 

我該怎麼做linq。

Answer 1

組行由ZONE字段的值，然後計算組值所有行的字段的總和（分組鍵將區名）：

var query = from r in table.AsEnumerable() 
      group r by r.Field<string>("ZONE") into g 
      select new { 
       Zone = g.Key, 
       TotalValue = g.Sum(r => r.Field<int>("Value")) 
      }; 

Answer 2

var results = (from r in dt.AsEnumerable() 
       group r by r.Field<string>("ZONE") into g 
       select new { 
        Zone = g.Key, 
        Sum = g.Sum(x => x.Field<int>("Value")) 
       }) 

或

var results = dt.AsEnumerable() 
       .GroupBy(
        x = > x.Field<string>("ZONE"), 
        (k, g) => new { ZONE = k, Sum = g.Sum(x => x.Field<int>("VALUE")) });