将Linq转换为Object到泛型对象的问题 [英] Convertin Linq to Object to a generic object problems

问题描述

我在从linq转换为通用对象时遇到问题，但是在这里失败了，我还有其他linqs查询，它们工作得很好.

我找不到错误的位置，并且我尝试了几种方法来完成此操作.失败的代码是这样的:

I''m having a problem with a conversion from linq to generic object, and it just fails here, I''ve others linqs querys and they work just fine.

I don''t find where the bug is and I''ve tried several ways to do the same. The code that is failing is this:

var queryT = from proc in DataContext.Procedimentos
                                 join ass in DataContext.Assistencias on proc.assistencia equals ass.codigo
                                 join mac in DataContext.Maquinas on ass.maquina equals mac.SN
                                 where ass.maquina == maq.SN
                                 select proc;

foreach (object procce in queryT)
                            {
                                Procedimento proccess = (Procedimento)procce;
                                TimeSpan span = proccess.fim.Subtract(proccess.inicio);
                                tempo = tempo + span.TotalHours;
                            }

在foreach指令中引发InvalidCastException

但是在调试模式下，我在监视(object)queryT.First()中编写了它，并且工作正常

throws InvalidCastException in the foreach instrution

but when in debug mode I write in the watch (object)queryT.First() and it works

推荐答案

好，发现了问题，问题出在那代码，但是在SQL表中，一个字段的类型不同于Procedimento类.

现在一切正常

Ok, found the problem, the problem was not in that code, but in the SQL table, one field had a different type from the class Procedimento...

Everything works now

尝试一下:

Try this:

List<object> queryT = null;
queryT = (from proc in DataContext.Procedimentos
          join ass in DataContext.Assistencias on proc.assistencia equals ass.codigo
          join mac in DataContext.Maquinas on ass.maquina equals mac.SN
          where ass.maquina == maq.SN
          select proc).ToList();

foreach...</object>

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