使用OR而不是AND链接/构建LINQ查询

编辑得更清楚。

例如，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 }; 

然后在方法中我想向它添加一个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 }; 

我该怎么做这个OR而不是AND？

PS不能使用PredicateBuilder，因为它本质上是LinqKit，它具有EntityFramework（≥6.0.2）的依赖性，我坚持使用EF 4.3.1

解决：感谢D Stanley（说实话我之前使用过这种forms的解决方案，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

你不能通过链接来做 – 你必须使用某种表达式构建器，或者只是在原始filter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 }; 

Answer 2

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);