順序，組和總結ExpandoObject中的數組列表c＃

Question

我想通過使用C＃Linq對「col1」和「col2」進行排序和分組來總結「col3」值。

List<dynamic> list = new List<dynamic>(); 

    dynamic expando = new ExpandoObject(); 
dynamic expando1 = new ExpandoObject(); 

    var p = expando as IDictionary<string, object>; 

    p["col1"] = "New val 1"; 
    p["col2"] = "New val 2"; 
    p["col3"] = 20; 

    list.Add(p); 

    var q = expando1 as IDictionary<string, object>; 

    q["col1"] = "New val 1"; 
    q["col2"] = "New val 3"; 
    q["col3"] = 10; 

    list.Add(q); 

我試圖讓輸出作爲

新VAL 1

• 新VAL 2
• 新VAL 3

---

合計 - 30

Answer 1

什麼是創造ExpandoObject，但使用它像一本字典的原因是什麼？如果你知道一組屬性（col1，col2，col3），最好爲它創建單獨的類，否則可以這樣做。

var list = new List<dynamic>(); 
dynamic e1 = new ExpandoObject(); 
e1.col1 = "New val 1"; 
e1.col2 = "New val 2"; 
e1.col3 = 20; 
list.Add(e1); 

dynamic e2 = new ExpandoObject(); 
e2.col1 = "New val 1"; 
e2.col2 = "New val 3"; 
e2.col3 = 10; 
list.Add(e2); 

foreach (var group in list 
    .OrderBy(e => e.col1) 
    .GroupBy(o => o.col1)) 
{ 
    Debug.WriteLine((string)group.Key); 
    var sum = 0; 
    foreach (var item in group) 
    { 
     Debug.WriteLine(" " + (string)item.col2); 
     sum += item.col3; 
    } 

    Debug.WriteLine("Total: " + sum); 
}