我正在使用 Dynamics sdk dll 的版本 5.0.9689.2165 并尝试使用 Linq
获取所有 Account.XDate
小于 Account.YDate
的帐户(两者都是自定义 DateTime
属性 - 我使用生成的代理类在项目中访问这些)从 Dynamics Online 帐户。
我有这个基本的表达方式:
var accounts = myOrganizationServiceContext.CreateQuery<Account>().Where(a => a.XDate < a.YDate)
但是当它被处理时我得到下面的异常 - 你不能比较服务器上的 2 个实体属性吗?
System.InvalidOperationException occurred
Message=variable 'a' of type 'Account' referenced from scope '', but it is not defined
Source=System.Core
StackTrace:
at System.Linq.Expressions.Compiler.VariableBinder.Reference(ParameterExpression node, VariableStorageKind storage)
at System.Linq.Expressions.Compiler.VariableBinder.VisitParameter(ParameterExpression node)
at System.Linq.Expressions.ExpressionVisitor.VisitMember(MemberExpression node)
at System.Linq.Expressions.ExpressionVisitor.Visit(ReadOnlyCollection`1 nodes)
at System.Linq.Expressions.Compiler.VariableBinder.VisitLambda[T](Expression`1 node)
at System.Linq.Expressions.Compiler.LambdaCompiler.Compile(LambdaExpression lambda, DebugInfoGenerator debugInfoGenerator)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.CompileExpression(LambdaExpression expression)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateExpressionToValue(Expression exp, ParameterExpression[] parameters)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateExpressionToConditionValue(Expression exp, ParameterExpression[] parameters)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhereCondition(BinaryExpression be, FilterExpressionWrapper parentFilter, Func`2 getFilter, Boolean negate)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhere(String parameterName, BinaryExpression be, FilterExpressionWrapper parentFilter, Func`2 getFilter, List`1 linkLookups, Boolean negate)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhereBoolean(String parameterName, Expression exp, FilterExpressionWrapper parentFilter, Func`2 getFilter, List`1 linkLookups, BinaryExpression parent, Boolean negate)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhere(String parameterName, BinaryExpression be, FilterExpressionWrapper parentFilter, Func`2 getFilter, List`1 linkLookups, Boolean negate)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhereBoolean(String parameterName, Expression exp, FilterExpressionWrapper parentFilter, Func`2 getFilter, List`1 linkLookups, BinaryExpression parent, Boolean negate)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.TranslateWhere(QueryExpression qe, String parameterName, Expression exp, List`1 linkLookups)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.GetQueryExpression(Expression expression, Boolean& throwIfSequenceIsEmpty, Boolean& throwIfSequenceNotSingle, Projection& projection, NavigationSource& source, List`1& linkLookups)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.Execute[TElement](Expression expression)
at Microsoft.Xrm.Sdk.Linq.QueryProvider.GetEnumerator[TElement](Expression expression)
我的电话就在这里
内部异常:
最佳答案
这代表了 CRM Linq 提供商的限制(又一次)。 Per Microsoft :
where
The left side of the clause must be an attribute name and the right side of the clause must be a value. You cannot set the left side to a constant. Both the sides of the clause cannot be constants.
要使用 Linq 提供程序解决您的特定问题,您可能必须在内存中收集整个 AccountSet
,然后对结果使用常规 Linq 方法以获得您想要的最终结果。
var accounts = myOrganizationServiceContext
.CreateQuery<Account>()
.Select(a => new { a.AccountId, a.XDate, a.YDate })
.ToList();
var filteredAccounts = accounts
.Where(a => a.XDate < a.YDate);
关于Linq to Dynamics - 比较 where 子句中的两个属性,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/11874133/