LINQ表达式树：针对DbSet调用任何方法

Question

我正在尝试将以下LINQ查询转换为表达式树

var queryActivity = uow.PromoActivityMeasuresRepository.ToQueryable();
var queryMeasure = uow.PromoMeasuresRepository.ToQueryable();
queryActivity.Where(pa => pa.WorkSpaceId == 28 && 
                          !queryMeasure.Any(pm => pm.WorkSpaceId == pa.WorkSpaceId && 
                                                  pm.Organization == pa.Organization && 
                                                  pm.MeasureCode == pa.MeasureCode));

我已经能够获得与简单约束相关的表达式，但是现在我仍然停留在如何创建与queryMeasure.Any相关的表达式上>

带代码

//I've translated pm.WorkSpaceId == pa.WorkSpaceId
var childParameter = Expression.Parameter(childEntityType, "pa");
var parentParameter = Expression.Parameter(validatingEntityType, "pm");
var parentWorkSpace = Expression.Property(parentParameter, "WorkSpaceId");
var childWorkSpace = Expression.Property(childParameter, "WorkSpaceId");
var parentChildWorkSpaceConstraint = Expression.Equal(parentWorkSpace, childWorkSpace); 

和代码

// I've translated pm => pm.WorkSpaceId == pa.WorkSpaceId && 
//                       pm.Organization == pa.Organization && 
//                       pm.MeasureCode == pa.MeasureCode)

Expression logicalAnd = null;
foreach (var field in FKChildEntity.Value.Fields)
{
    var parentLeft = Expression.Property(parentParameter, field);
    var childRight = Expression.Property(childParameter, field);
    var parentChildConstraint = Expression.Equal(parentLeft, childRight);
    if (logicalAnd == null)
    {
        logicalAnd = Expression.AndAlso(parentChildWorkSpaceConstraint, parentChildConstraint);
        continue;
    }
    //parentConstraints.Add(parentChildConstraint);
    logicalAnd = Expression.AndAlso(logicalAnd, parentChildConstraint);
}
这里是问题...

我不明白如何调用queryMeasure。以后在NegateExpression中将要使用的任何东西

var parentDelegateType = typeof(Func<,>).MakeGenericType(validatingEntityType, typeof(bool));
var parentPredicate = Expression.Lambda(parentDelegateType, logicalAnd, parentParameter);
var promoMeasuresParameter = Expression.Constant(dataRepository, dataRepository.GetType());

var AnyMethod = Expression.MakeMemberAccess(promoMeasuresParameter, promoMeasuresParameter.GetType().GetMember("Any").FirstOrDefault());

var parentQueryable = dataRepository.GetType().InvokeMember("ToQueryable", BindingFlags.InvokeMethod, null, dataRepository, null);
var collectionParameter = Expression.Parameter(parentQueryable.GetType(), "parentCollection");

var AnyMethodExpression = Expression.Call(parentQueryable.GetType(), "Any", null , parentPredicate);
var negateExpression = Expression.Negate(AnyMethodExpression);

我可以问你们中的一些如何进行的提示吗？

谢谢大家

我正在尝试将以下LINQ查询转换为表达式树var queryActivity = uow.PromoActivityMeasuresRepository.ToQueryable（）; var queryMeasure = uow.PromoMeasuresRepository.ToQueryable（...

Answer 1

您要调用的Any方法是通用的（Where也是如此：