我有一个扩展方法 IsAssignableFrom
public static bool IsTypeOf<T>(this Type type)
{
return typeof (T).IsAssignableFrom(type);
}
由以下人员调用:
var Type = typeof(BadgeNumVotesOnItem);
var UnlockableBadges = DB.Badges.Where(t => t.GetType().IsAssignableFrom(Type));
但是,当我使用它时,它会抛出此异常:
{System.NotSupportedException: LINQ to Entities does not recognize the method 'Boolean IsAssignableFrom(System.Type)' method, and this method cannot be translated into a store expression.
at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.DefaultTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
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 MVCDaemon.Helpers.AwardBadgesProcessor.AwardBadgesForEventViewedSituation() in c:\Users\William-Business\Desktop\TWB\Entrepreneurial dev\Hehe\Hehe.Daemon\Processors\hehehe.cs:line 27
at MVCDaemon.Controllers.AwardBadgesController.FromUnprocessedEvents() in c:\Users\William-Business\Desktop\TWB\Entrepreneurial dev\Hehe\Hehe.Daemon\Controllers\hehehe.cs:line 29}