English 中文(简体)
当用林盖进行收集时,总是会恢复无效。
原标题:When querying a collection using linq it always returns a null

第二天,我张贴了部分法典,但这样做造成了更多的混乱。 这是我的法典。

if ( HttpContext.Current.Session != null )
{
                if ( HttpContext.Current.Session[ "CurrentLabourTransactions" ] != null )
                {
                    Collection<JCTransLabour> oJCTransLabours = null;

                    oJCTransLabours = (Collection<JCTransLabour>)HttpContext.Current.Session["CurrentLabourTransactions"];

                    if (Settings.ShowTodaysTransactionInApproval)
                        if (oJCTransLabours != null) return oJCTransLabours;


                    if (oJCTransLabours != null)
                    {
//oJCtransLabour contains alot of record
                        var oCurrentLabourTrans = (from clt in oJCTransLabours
                                                   where clt.TransactionDate.Date != DateTime.UtcNow
                                                   select clt);
//oCurrentLabourTrans is null.
                        return oCurrentLabourTrans as Collection<JCTransLabour>;
                    }
                }
            }
            return null;

如果报表内有许多日期不同的交易,则在作最后处理。 看来,尽管它总是放弃记录。

事先得到任何帮助。

最佳回答

这条路线是:

return oCurrentLabourTrans as Collection<JCTransLabour>;

not a Collection<JCtransLabour>,从而按预期,as营运收益无效。 如果是这样的话:

return (Collection<JBTransLabour) oCurrentLabourTrans;

投稿将失败,将扔下“InvalidCastException。 LINQ 操作员直接生产以下物品:IE 可根据数字加附;>;不自动生成收集和列出物体。

如果您必须交回<代码>Collection<>,你可以这样做:

return new Collection<JCTransLabour>(oCurrentLabourTrans.ToList());
问题回答

暂无回答




相关问题
Anyone feel like passing it forward?

I m the only developer in my company, and am getting along well as an autodidact, but I know I m missing out on the education one gets from working with and having code reviewed by more senior devs. ...

NSArray s, Primitive types and Boxing Oh My!

I m pretty new to the Objective-C world and I have a long history with .net/C# so naturally I m inclined to use my C# wits. Now here s the question: I feel really inclined to create some type of ...

C# Marshal / Pinvoke CBitmap?

I cannot figure out how to marshal a C++ CBitmap to a C# Bitmap or Image class. My import looks like this: [DllImport(@"test.dll", CharSet = CharSet.Unicode)] public static extern IntPtr ...

How to Use Ghostscript DLL to convert PDF to PDF/A

How to user GhostScript DLL to convert PDF to PDF/A. I know I kind of have to call the exported function of gsdll32.dll whose name is gsapi_init_with_args, but how do i pass the right arguments? BTW, ...

Linqy no matchy

Maybe it s something I m doing wrong. I m just learning Linq because I m bored. And so far so good. I made a little program and it basically just outputs all matches (foreach) into a label control. ...

热门标签