無法從字典轉換為IDictionary

Question

我正在嘗試使用方法創建接口

void Import(int id, IDictionary<int, IDictionary<int, string>> items);

然后像這樣調用此方法

Dictionary<int, Dictionary<int, string>> items = viewModel.Items
  .GroupBy(t => t.Number)
  .ToDictionary(t => t.Key, t => t.ToDictionary(x => x.LanguageId, x => x.Translation));


Import(id, items);

我期望它應該可以工作但是出現錯誤

cannot convert from 'System.Collections.Generic.Dictionary<int, System.Collections.Generic.Dictionary<int, string>>' to 'System.Collections.Generic.IDictionary<int, System.Collections.Generic.IDictionary<int, string>>'  

為什么我在這里不能使用接口IDictionary？ 我應該手動投放嗎？

Answer 1

更改您的分配類型。

Dictionary<int, IDictionary<int, string>> items = viewModel.Items
  .GroupBy(t => t.Number)
  .ToDictionary(t => t.Key, t => (IDictionary<int, string>) t.ToDictionary(x => x.LanguageId, x => x.Translation));