小编Nul*_*nce的帖子

我正在尝试做以下事情......

Request request = (
     from r in db.Requests 
     where r.Status == "Processing" && r.Locked == false 
     select r
).SingleOrDefault();

抛出以下异常......

Message:
Specified cast is not valid.

StackTrace:
   at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult)
   at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries)
   at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)
   at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression)
   at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source)
   at GDRequestProcessor.Worker.GetNextRequest()

谁能帮我？提前致谢!

架构细节可以在下面找到...

[Table(Name="dbo.Requests")]
public partial class Request : INotifyPropertyChanging, INotifyPropertyChanged
{

    private static PropertyChangingEventArgs emptyChangingEventArgs …

我试图访问GridView中的PagerTemplate内的LinkBut​​ton.

但是,我得到一个NullReferenceException并且我不知道我在这里做错了什么.

我试过以下......

((LinkButton)GridView1.BottomPagerRow.FindControl("lnkbtnPrevious"));
((LinkButton)GridView1.FindControl("lnkbtnPrevious"));

有人可以帮忙吗？

谢谢!