我认为编译的查询将执行与DataContext相同的查询转换.但是当我尝试使用带有.Contains方法调用的查询时,我遇到了运行时错误.我哪里出错了？
//private member which holds a compiled query.
Func<DataAccess.DataClasses1DataContext,List<int>,List<DataAccess.TestRecord>>
compiledFiftyRecordQuery = System.Data.Linq.CompiledQuery.Compile
<DataAccess.DataClasses1DataContext,List<DataAccess.TestRecord>>
((dc,ids) => dc.TestRecords.Where(tr => ids.Contains(tr.ID)).ToList());
//this method calls the compiled query.
public void FiftyRecordCompiledQueryByID()
{
List<int> IDs = GetRandomInts(50);
//System.NotSupportedException
//{"Parameters cannot be sequences."}
List<DataAccess.TestRecord> results = compiledFiftyRecordQuery
(myContext,IDs);
}
解决方法
This article有你的答案：
Queries with list parameters cannot be precompiled because the translation of the query is dependent on the number of items in the list.
