Question

由于我已经切换到.net 4.5和EF 5.0，我已经开始使用枚举映射。在我的项目中，我首先使用模型。因为所有的枚举都是早先声明的，所以当我在EDM中将字段转换为枚举时，我决定使用选项“引用外部类型”。一切正常，但是当我尝试执行像

这样的代码时

public enum SomeEnum : int
{
    value1 = 0,
    value2 = 1
}

class Program
{
    static void Main(string[] args)
    {
        TestDbEntities context = new TestDbEntities();
        var enumList = new List<SomeEnum>() { SomeEnum.value1, SomeEnum.value2 };
        var items = context.Table1.Where(e => enumList.Contains(e.EnumField));
        foreach (var item in items)
        {
            Console.Write(item.Id);
        }
        context.Dispose();
    }
}

我收到带有消息的ArgumentException：

The type 'SomeEnum' does not match the EDM enumeration type 'SomeEnum' or its underlying type 'Int32' Parameter name: value.

有线的是，当我不使用参考外部类型时，一切都很好。我理解EDM背后的原因，但我无法理解为什么这个代码在模型中定义枚举后由T4生成

  <EntityContainer Name="TestDbEntities" p1:LazyLoadingEnabled="true">
      <EntitySet Name="Table1" EntityType="TestDbModel.Table1" />
    </EntityContainer>
    <EntityType Name="Table1">
      <Key>
        <PropertyRef Name="Id" />
        <PropertyRef Name="EnumField" />
      </Key>
      <Property Name="Id" Type="Int32" Nullable="false" />
      <Property Name="EnumField" Type="TestDbModel.SomeEnum" Nullable="false" />
    </EntityType>
    <EnumType Name="SomeEnum" a:ExternalTypeName="ConsoleApplication1.SomeEnum" xmlns:a="http://schemas.microsoft.com/ado/2006/04/codegeneration" />

我想使用引用外部类型，但这是一些限制。我知道我可以转换为基础类型，但这是一个黑客。

----编辑这是一个堆栈跟踪

at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.ArgumentValidation.ValidateConstant(TypeUsage constantType, Object value)
at System.Data.Objects.ELinq.ExpressionConverter.ConstantTranslator.TypedTranslate(ExpressionConverter parent, ConstantExpression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.NewArrayInitTranslator.<>c__DisplayClass88.<TypedTranslate>b__86(Expression e)
at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.EnumerableValidator`3.Validate(IEnumerable`1 argument, String argumentName, Int32 expectedElementCount, Boolean allowEmpty, Func`3 map, Func`2 collect, Func`3 deriveName)
at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.EnumerableValidator`3.Validate()
at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.ArgumentValidation.CreateExpressionList(IEnumerable`1 arguments, String argumentName, Boolean allowEmpty, Action`2 validationCallback)
at System.Data.Common.CommandTrees.ExpressionBuilder.Internal.ArgumentValidation.ValidateNewCollection(IEnumerable`1 elements, DbExpressionList& validElements)
at System.Data.Common.CommandTrees.ExpressionBuilder.DbExpressionBuilder.CreateNewCollection(IEnumerable`1 elements)
at System.Data.Objects.ELinq.ExpressionConverter.NewArrayInitTranslator.TypedTranslate(ExpressionConverter parent, NewArrayExpression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.ConstantTranslator.TypedTranslate(ExpressionConverter parent, ConstantExpression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.ContainsTranslator.TranslateContains(ExpressionConverter parent, Expression sourceExpression, Expression valueExpression)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.ContainsTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SequenceMethodTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, SequenceMethod sequenceMethod)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input, DbExpressionBinding& binding)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.OneLambdaTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, DbExpression& source, DbExpressionBinding& sourceBinding, DbExpression& lambda)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.OneLambdaTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SequenceMethodTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, SequenceMethod sequenceMethod)
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Objects.ELinq.ExpressionConverter.Convert()
at System.Data.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
at System.Data.Entity.Internal.Linq.InternalQuery`1.GetEnumerator()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Collections.Generic.IEnumerable<TResult>.GetEnumerator()
at ConsoleApplication1.Program.Main(String[] args) in c:\Users\Pawel\Documents\Visual Studio 2012\Projects\ClassLibrary1\ConsoleApplication1\Program.cs:line 22
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

Answer 1

这是一个错误。我在EntityFramework Codeplex网站上提交了它：http://entityframework.codeplex.com/workitem/623。目前解决方法是使用||或者在EDM枚举类型中指定CLR枚举类型中的所有成员。设置外部枚举类型会向EDM枚举类型（a：ExternalTypeName =“ConsoleApplication1.SomeEnum”）添加注释，该类型告诉代码gen不生成此类型，但在生成的代码中使用该属性的值，使用该类型。如果没有此注释，将生成与EDM枚举类型完全匹配的CLR枚举。顺便说一句。不久前我在EF5和外部枚举类型上写了一篇博文。你可以在这里找到它：http://blog.3d-logic.com/2012/09/11/using-exisiting-enum-types-in-entity-framework-5/。我将在博客上添加有关该错误的信息。随意评论它。

Answer 2

不是直接的解决方案，但这种解决方法符合我的要求。

var enumList = new List<int>() { (int)SomeEnum.value1, (int)SomeEnum.value2 }; 
var items = context.Table1.Where(e => enumList.Contains((int)e.EnumField));

引用外部类型枚举并包含方法

2 个答案: