Question

编辑得更清楚。

例如，如果我有这个IQueryable：

DateTime theDate = new DateTime(2015, 09, 30);

var query = from org in Organisations
            where org.DisableOrganisation == false &&
              org.DisableReports == false
            select new
            {
                OrganisationId = org.OrganisationId
            };

以后在方法中我想为它添加一个OR，例如

// Check to see if the date is the last day of the month.
if (theDate.AddDays(1).Day == 1)
{
    // The following statement introduces an AND but I want to make this an OR.
    query = query.Where(x => x.Frequency == "M");
}

这有效地使我的查询......

var query = from org in Organisations
            where org.DisableOrganisation == false &&
              org.DisableReports == false &&
              org.Frequency == "M"
            select new
            {
                OrganisationId = org.OrganisationId
            };

但我想成功......

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
              org.DisableReports == false) ||
              org.Frequency == "M"
            select new
            {
                OrganisationId = org.OrganisationId
            };

如何将其设为OR而不是AND？

P.S。不能使用PredicateBuilder，因为它本质上是LinqKit，它具有EntityFramework（≥6.0.2）的依赖性，我使用EF 4.3.1

已解决：感谢D Stanley（说实话我之前使用过这种解决方案，我只是忘了它。）

DateTime theDate = new DateTime(2015, 09, 30);
bool isEndOfMonth = theDate.AddDays(1).Day == 1;

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
              org.DisableReports == false) ||
              (isEndOfMonth &&
               pr.ProfileType == "L" && 
               pr.Frequency == "M")
            select new
            {
                OrganisationId = org.OrganisationId
            };

Answer 1

要将条件与OR而不是AND组合，请使用PredicateBuilder:

predicate = predicate.Or(p => p.Description.Contains (temp));
return dataContext.Products.Where(predicate);

Answer 2

你不能通过链接来实现 - 你必须使用某种表达式构建器，或者只是在原始过滤器中构建它：

var day = theDate.AddDays(1).Day;

var query = from org in Organisations
            where (org.DisableOrganisation == false &&
                   org.DisableReports == false) ||
                  (day == 1 &&
                   org.ProfileType == "L" && 
                   org.Frequency == "M")
            select new
            {
                OrganisationId = org.OrganisationId
            };

使用OR而不是AND

2 个答案: