从SQL创建LINQ

Question

我想从后面的Sql创建Linq查询，但无法让它工作。

SQL

"select distinct(roomName) as RoomName, tblroomid as RoomId 
from TblMaster,tblrooms 
where tblrooms.tblroomid = TblPresentationMaster.tblroomid 
and convert(datetime, PDay, 101)='" + Pday + "'"; 

LINQ

(from tblRoom in tblRooms.AsEnumerable() 
join tblPMaster in tblMaster.AsEnumerable() 
on tblRoom.Field<int>("tblroomid") equals tblPMaster.Field<int>("tblroomid") 
where tblPMaster.Field<string>("pday") == Pday 
select tblRoom.Field<string>("roomName")).Distinct(); 

如果我尝试运行它

foreach (var myReader in query) 
{ 
} 

我收到以下错误

指定的转换无效。

这些都是在下面的变量值，希望这有助于在捕获错误

tblPMaster.pday = Jun 28 2011 12:00AM 
Parameter Pday = 28/11/2011 

我不知道我做错了。有人可以帮助获得正确的LINQ查询吗？

Answer 1

@javadotnetcoder，感谢您的澄清。我想我找到了解决办法...

试试：

DataTable tblMaster = new DataTable(); 
DataColumn dc = new DataColumn("pday", Type.GetType("System.String")); 
tblMaster.Columns.Add(dc); 
tblMaster.Rows.Add(new Object[]{"Nov 28 2011 12:00AM"}); 
tblMaster.Rows.Add(new Object[]{"Apr 27 2013 11:10PM"}); 
tblMaster.Rows.Add(new Object[]{"Jul 18 2011 12:00AM"}); 
tblMaster.Rows.Add(new Object[]{"Mar 19 2012 10:01PM"}); 

DateTime PDay = new DateTime(2011,11,28); 

//foreach(var row in tblMaster.AsEnumerable()) 
//{ 
// Console.WriteLine("{0}", Convert.ToDateTime(row[0])); 
//} 

var qry = tblMaster.AsEnumerable() 
     .Where(p=>Convert.ToDateTime(p.Field<string>("pday"))==PDay); 
//qry.Dump(); 

上述代码在LinqPad进行了测试。也可以;

干杯，Maciej

Answer 2

投这个至今没有串

tblPMaster.Field<string>("pday")