3

我有以下代码:

List<Type> p1 = new List<Type>();
p1.Add(typeof(int));
p1.Add(typeof(string));
dynamic genericDic = typeof(Dictionary<, >);
dynamic specificDic1 = genericDic.MakeGenericType(p1.ToArray());
dynamic dic1 = Activator.CreateInstance(specificDic1);
dic1.Add(1, "John");
dic1.Add(2, "Smith");
dynamic genericLst = typeof(List<>);
dynamic specificLst = genericLst.MakeGenericType(typeof(string));
dynamic list = Activator.CreateInstance(specificLst);
list.AddRange(dic1.Values.ToList());

当我尝试执行时,list.AddRange(dic1.Values.ToList());我得到以下异常

未找到类型“ValueCollection”的公共成员“ToList”。

堆栈跟踪:

   at Microsoft.VisualBasic.CompilerServices.Symbols.Container.GetMembers(String& MemberName, Boolean ReportErrors)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.ObjectLateGet(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateGet(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack)
   at StyleResearch.DataManagement.DataStream.Business.MonthEndProcess.ConverToLegacyStructureInMemory(List`1 marketDataTypeIds, String tableName, Int32 placeHolderValue) in C:\Style Research\Work\SRDM\trunk\StyleResearch.DataManagement.DataStream.Business\MonthEndProcess.vb:line 1850
   at StyleResearch.DataManagement.DataStream.UI.DDLMonthEndProcess._Lambda$__6(LegacyStructureDetail legacy) in C:\Style Research\Work\SRDM\trunk\StyleResearch.DataManagement.DataStream.UI\DDLMonthEndProcess.vb:line 1198
   at System.Threading.Tasks.Parallel.<>c__DisplayClass2d`2.<ForEachWorker>b__23(Int32 i)
   at System.Threading.Tasks.Parallel.<>c__DisplayClassf`1.<ForWorker>b__c()

注意:我已将 VB.NET 示例转换为 C#,但堆栈跟踪来自 VB.NET 项目

当我执行以下操作时,它工作得非常好:

Dictionary<int, string> dic = new Dictionary<int, string>();
dic.Add(1, "John");
dic.Add(2, "Smith");
List<string> lst = new List<string>();
lst.AddRange(dic.Values.ToList());
4

4 回答 4

3

只需投射它:

list.AddRange(((IEnumerable<string>)dic1.Values).ToList());

此外,您可以再次通过动态:

list.AddRange((dynamic)dic1.Values));
于 2012-07-05T10:43:17.917 回答
2

ToList<T>() 是 IEnumerable<T> 的扩展方法。但是您的 dic1.Values 是动态类型而不是 IENumerable<string> 所以.Net 无法找到并使用这种扩展方法。您可以尝试简单的 foreach:

foreach (var value in dic1.Values)
  list.Add(value)
于 2012-07-05T10:40:14.437 回答
0

尝试在没有扩展函数语法的情况下调用,即类似

Enumerable.ToList ( (dynamic) dic1.Values )

DLR 不会在运行时搜索继承接口的扩展函数(我猜是出于性能原因或避免歧义)。

于 2012-07-05T11:56:16.197 回答
0
list.AddRange((IEnumerable<string>)dic.Values))

或者

List<string> list = ((IEnumerable<string>)dic.Values).ToList();

或者

List<string> list = new List<string>((IEnumerable<string>)dic.Values);
于 2012-07-05T10:44:42.340 回答