[英]Null exception in LINQ statement, but returns results in LINQPAD
我下面有一個LINQ語句,該語句應將110條記錄返回到我的視圖。 當我檢查SQL Server時,我的表中有記錄,但是當我嘗試基於一個ID檢索這些記錄並執行@foreach(var item in Model)
導致空引用錯誤。 任何幫助,將不勝感激。
LINQPAD-返回110條記錄(RPT是模式)
RPT.Team_History.OrderByDescending (r => r.DateOfAction).Where(r => r.MgrID ==212)
控制器代碼 (使用DB First方法。當VS生成模型時,刪除了RPT模式)
public PartialViewResult _TeamTransitionDisplay()
{
var mgrID = 212;
IEnumerable<TeamHistoryViewModel> teamHistory;
teamHistory = db.Team_History
.Where(x => x.MgrID == @mgrID)
.Select(x => new TeamHistoryViewModel
{
DateOfAction = x.ActionDate,
DeptID = x.DeptID,
Operation = x.Operation,
StartDate = x.StartDate,
AStartDate = x.AStartDate,
FStartDate = x.FStartDate
}).ToList();
return PartialView("_TeamDisplay", teamHistory);
}
[NullReferenceException:對象引用未設置為對象的實例。
意見將不勝感激。
我認為,當它嘗試獲取您的模型值之一時,它可能為null,因此引發錯誤。您可以嘗試對可為空的屬性添加此檢查,如果只有nullable,則檢查是否為null,我添加了所有這些,因為我不知道哪個可以為空
teamHistory = db.Team_History
.Where(x => x.MgrID == @mgrID)
.Select(x => new TeamHistoryViewModel
{
DateOfAction = (x.ActionDate != null ? x.ActionDate : something here when null),
DeptID = (x.DeptID!= null ? x.DeptID: 0),
Operation = (x.Operation!= null ? x.Operation: "operation"),
StartDate = (x.StartDate!= null ? x.StartDate: DateTime.MinValue),
AStartDate = (x.AStartDate != null ? x.AStartDate : DateTime.MinValue),
FStartDate = (x.FStartDate != null ? x.FStartDate : DateTime.MinValue)
}).ToList();
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