我是一名新手,对C#和Linq不熟悉。
实际上,我想将匿名类型返回到列表中。这个匿名类型包含List、String和DateTime。我尝试使用下面的代码,但是它会报错。请帮忙告诉我哪里出了问题,或者建议如何实现这个目标。
//错误:
System.InvalidCastException: Specified cast is not valid..
//编辑后的 C# Linq 代码
public List<AuditInfo> GetScanAudit(object Id, DateTime? fromTime, DateTime? toTime, string type = null,
string user = null, Pager pager = null)
{
using (var ctx = new PlantDataContext())
{
var query = from audit in ctx.AuditLog
join ent in ctx.Scans on audit.RecordId equals ent.Id.ToString() into audits
from entaudits in audits.DefaultIfEmpty()
where audit.TypeFullName == "ABCD.DB.Model.Scan"
select new
{
audit,
entaudits
};
if (Id != null)
{
query = query.Where(x => x.audit.RecordId == Id.ToString());
}
if (fromTime.HasValue)
{
var tmp = new DateTimeOffset(fromTime.Value.ToUniversalTime());
query = query.Where(x => x.audit.EventDateUTC >= tmp);
}
if (toTime.HasValue)
{
var tmp = new DateTimeOffset(toTime.Value.ToUniversalTime());
query = query.Where(x => x.audit.EventDateUTC <= tmp);
}
if (!string.IsNullOrEmpty(type))
{
var parseEvent = (EventType)Enum.Parse(typeof(EventType), type);
query = query.Where(x => x.audit.EventType == parseEvent);
}
if (!string.IsNullOrEmpty(user))
{
query = query.Where(x => x.audit.UserName == user);
}
if (pager != null)
{
var totalRecords = query.Count();
pager.TotalRecords = totalRecords;
var data = query.Select(x =>
new AuditInfo
{
x.audit.TypeFullName, //Here Error Occurs
x.audit.UserName,//Here Error Occurs
x.audit.EventType,//Here Error Occurs
x.audit.EventDateUTC,//Here Error Occurs
@LogDetails = x.audit.LogDetails.ToList(), //Here Error Occurs
x.entaudits.Name,
@Description = x.entaudits.Description
})
.OrderByDescending(x => x.EventDateUTC)
.Skip(pager.From)
.Take(pager.PageSize);
try
{
var list1 = data.ToList<AuditInfo>();
}
catch (Exception e)
{
}
var list = data.ToList<AuditInfo>();
pager.RecordCount = list.Count;
return list;
}
else
{
var list = query.Select(x =>
new AuditInfo
{
x.audit.TypeFullName,
x.audit.UserName,
x.audit.EventType,
x.audit.EventDateUTC,
@LogDetails = x.audit.LogDetails.ToList(),
x.entaudits.Name,
@Description = x.entaudits.Description
})
.OrderByDescending(x => x.EventDateUTC)
.ToList<AuditInfo>();
return list;
}
}
}
当我调试代码时,totalRecords变量显示计数为6,但在这一行var list1 = data.ToList()处显示异常信息Specified cast is not valid。
sql
标签在这里是否相关。 - Caius JardGetScanAudit
,为什么选择返回类型为List<dynamic>
而不是List<SomeClass>
? - er-sho.OrderByDescending(x => x.EventDateUTC).Cast<dynamic>().ToList()
。 - Alessandro D'Andria