C#中集合的加工处理方法

1.Linq中自带的计算方法：Sql.

。

2.GroupBy 用法

OcSheetNameInfo = OcFlowCheckTableNameConfig
.GroupBy(flowBase => flowBase.FunctionTableName)
.Select(S => new FlowCheckTableNameConfig { FunctionTableName = S.Key }).ToObservableCollection();

var mult = OcItemsTemp.GroupBy(g => new { g.MaterialID, g.TargetObjectID, }).Where(w => w.Count() > 1).ToList();

3.Dictonary

从字典（DicRoleForScope）中查询对应（role）的值再赋值给其他变量（ DicSelectedRoleForScope）

 Dictionary<string, object> dic = DicRoleForScope.Where(s => s.Value.ToString().Contains(role)).
                    Select(q => new { q.Key, q.Value }).
                    ToList().AsEnumerable().ToDictionary(d => d.Key, d => (object)d.Value);  // where对比中使用Contains
               
 KeyValuePair<string, object> kvp = dic.FirstOrDefault();
             
   if (kvp.Key != null && kvp.Value != null)  //注意判断为空否
   {
        DicSelectedRoleForScope.Add(kvp.Key, kvp.Value); //Dictionary只能以键值对的形式添加
   }         

　4.获取ID数组

int[] ids = entityList.Select(v => v.ID).ToArray();

　5.汇总

 OcOutStock.Sum(t => t.Amount).ToDecimal();