为调用方法'Boolean Equals提供的参数数量不正确

Question

为调用方法'Boolean Equals提供的参数数量不正确

为什么我得到一个参数异常,说我将错误数量的参数传递给string.equals方法？

我传递了三个论点,这应该是正确的.实际上它应该抛出编译时错误而不是运行时...

你看到错误吗？

var translations = await (from l in context.Languages
                  join t in context.Translations on l.ISO639_ISO3166 equals t.ISO639_ISO3166
                  where string.Equals(l.ApplicationName, applicationName, StringComparison.InvariantCultureIgnoreCase)
                  select new Translation
                  {
                      Key = t.Key,
                      Text = t.Text
                  }).ToListAsync();

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UPDATE

Test Name:  GetTranslations
Test FullName:  TaaS.IntegrationTests.Tests.TranslationRepositoryTests.GetTranslations
Test Source:    C:\test\TaaS-WebApplication\TaaS.IntegrationTests\Tests\TranslationRepositoryTests.cs : line 17
Test Outcome:   Failed
Test Duration:  0:00:00,0473367

Result StackTrace:  
at System.Linq.Expressions.Expression.GetMethodBasedBinaryOperator(ExpressionType binaryType, Expression left, Expression right, MethodInfo method, Boolean liftToNull)
   at System.Linq.Expressions.Expression.Equal(Expression left, Expression right, Boolean liftToNull, MethodInfo method)
   at System.Data.Entity.Core.Objects.ELinq.LinqExpressionNormalizer.VisitMethodCall(MethodCallExpression m)
   at System.Linq.Expressions.EntityExpressionVisitor.Visit(Expression exp)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitLambda(LambdaExpression lambda)
   at System.Linq.Expressions.EntityExpressionVisitor.Visit(Expression exp)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitUnary(UnaryExpression u)
   at System.Linq.Expressions.EntityExpressionVisitor.Visit(Expression exp)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitExpressionList(ReadOnlyCollection`1 original)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitMethodCall(MethodCallExpression m)
   at System.Data.Entity.Core.Objects.ELinq.LinqExpressionNormalizer.VisitMethodCall(MethodCallExpression m)
   at System.Linq.Expressions.EntityExpressionVisitor.Visit(Expression exp)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitExpressionList(ReadOnlyCollection`1 original)
   at System.Linq.Expressions.EntityExpressionVisitor.VisitMethodCall(MethodCallExpression m)
   at System.Data.Entity.Core.Objects.ELinq.LinqExpressionNormalizer.VisitMethodCall(MethodCallExpression m)
   at System.Linq.Expressions.EntityExpressionVisitor.Visit(Expression exp)
   at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter..ctor(Funcletizer funcletizer, Expression expression)
   at System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.CreateExpressionConverter()
   at System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClassc.<GetResultsAsync>b__a()
   at System.Data.Entity.Core.Objects.ObjectContext.<ExecuteInTransactionAsync>d__3d`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<ExecuteAsyncImplementation>d__9`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter`1.GetResult()
   at System.Data.Entity.Core.Objects.ObjectQuery`1.<GetResultsAsync>d__e.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Data.Entity.Utilities.TaskExtensions.CultureAwaiter`1.GetResult()
   at System.Data.Entity.Internal.LazyAsyncEnumerator`1.<FirstMoveNextAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Data.Entity.Infrastructure.IDbAsyncEnumerableExtensions.<ForEachAsync>d__5`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TaaS.Repository.TranslationRepository.<GetTranslationsAsync>d__2.MoveNext() in C:\_REPOSITORIES\taas-application\TaaS-WebApplication\TaaS.Repository\TranslationRepository.cs:line 20
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at TaaS.IntegrationTests.Tests.TranslationRepositoryTests.GetTranslations() in C:\_REPOSITORIES\taas-application\TaaS-WebApplication\TaaS.IntegrationTests\Tests\TranslationRepositoryTests.cs:line 45
Result Message: 
Test method TaaS.IntegrationTests.Tests.TranslationRepositoryTests.GetTranslations threw exception: 
System.ArgumentException: Incorrect number of arguments supplied for call to method 'Boolean Equals(System.String, System.String, System.StringComparison)'

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Answer 1

Pan*_*vos 28

首先,SQL字符串比较不区分大小写,或者说,最常见的排序规则不区分大小写.

您根本不需要使用String.Equals.尝试执行查询,而不该String.Equals呼叫.

如果由于某种原因,查询无法返回结果,则参数或数据可能存在问题.你应该尝试直接执行相当于SQL语句,并检查是否存在有任何匹配的结果.

仅当基础列的排序规则被修改为对字符串敏感的排序规则时,字符串大小写才是问题.这将是非常不寻常的.事实上,困难的部分是让LINQ to EF做一个区分大小写的查询.

至于错误本身,它是由于String.Equals无法转换为SQL 而引起的.LINQ本身不执行查询,它只是一种语言.LINQ提供程序负责将查询转换为底层语言并执行它们.

某些提供程序(如LINQ to SQL)将解析它们可能的任何内容,将结果加载到内存中并将其传递给LINQ to Object以获取不受支持的操作.这通常会导致非常糟糕的性能.在您的情况下,您的查询将加载内存中的所有翻译,然后尝试过滤它们.

另一方面,LINQ to EF不允许这样做以防止性能问题.无法执行的查询不会被执行.String.Equals特别是不能转换为SQL,因为字符串比较由特定于文化的排序规则控制.没有与Invariant Culture相同的文化.

如果你的表是大小写敏感的,你必须改变用于比较的排序规则,例如对Latin1_CI_AS.这个问题描述了各种方法

感谢不区分大小写的评论.真的有帮助! (2认同)

Answer 2

cod*_*zen 11

这是一个运行时错误,因为您可能正在运行Linq查询提供程序,该提供程序接受一个C#编译器从C#代码创建的表达式并在运行时执行它.提供者可能无法转换Equals的这种重载.

尝试将您的Linq查询更改为:

(from l in context.Languages
join t in context.Translations on l.ISO639_ISO3166 equals t.ISO639_ISO3166).AsEnumerable()
.Where(l => string.Equals(l.ApplicationName, applicationName, StringComparison.InvariantCultureIgnoreCase))
.Select(new Translation
              {
                  Key = t.Key,
                  Text = t.Text
              }).ToListAsync();

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我将比较更改为"==",因为这是我想再次记住,由于@Panagiotis Kanavos,sql比较不区分大小写. (3认同)
这不是一个好答案，因为`AsEnumerable（）`会加载内存中的所有行，然后尝试应用“ WHERE”条件而没有索引的好处。而不是从100K表中加载10行，而是将加载所有10万行 (3认同)

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