我知道这个问题多次问过，但我找不到任何可以帮助我的答案
问题是 -contextcontext-instance-has-dispos-and-can-no-used-for-operations-that-require-a-connection
在我声明已链接到具有1对多关系的其他实体的实体对象的副本
之后这是班级
using System;
using System.Linq;
using School.Component;
using System.Windows.Input;
using DataAccess;
using System.Collections.ObjectModel;
using DataAccess.Repository;
using Microsoft.Practices.Prism.Commands;
using System.Collections.Generic;
namespace School.WpfApp.ViewModels
{
public class LevelsPerYearNewVM : ViewModelBase
{
SchAvaiLevelsPerYear _CurrentLevelsPerYear;
SchAvaiLevelsPerYear _old;
private bool _isnew = false;
bool _IsEnabled = false;
StudyYearRepository _Repository = new StudyYearRepository();
SchoolSettingRepository _SRepository = new SchoolSettingRepository();
ObservableCollection<StageLevel> _AllStageLevel;
StageLevel _SelectrdStageLevel;
ObservableCollection<SchAvaiLevelsPerYear> _allSchAvaiLevelsPerYear;
ObservableCollection<CoursesLevelsPerStYear> _AllCoursesLevelsPerStYear;
private string errorMasseg;
public LevelsPerYearNewVM(SchAvaiLevelsPerYear f, ObservableCollection<SchAvaiLevelsPerYear> _list)
: base()
{
_old = (f);
CurrentLevelsPerYear = new SchAvaiLevelsPerYear()
{
Avalible = f.Avalible,
CoursCount = f.CoursCount,
YearID = f.YearID,
ID = f.ID,
SchoolID = f.SchoolID,
UserID = f.UserID,
StageLevelID = f.StageLevelID,
};
InitVars();
CreateCommands();
ErrorMasseg = "";
if (_CurrentLevelsPerYear.ID > 0)
{
this.Title = "تعديل بيانات المستوى الدراسي";
}
else
{ this.Title = "اضافة مستوى دراسي"; IsEnabled = true; _isnew = true; }
_allSchAvaiLevelsPerYear = _list;
}
protected override async void InitVars()
{
AllStageLevel = await _SRepository.GetAllStageLevelsIncludeCourses();
if(!isnew)
AllCoursesLevelsPerStYear = await _SRepository.GetAllAllCoursesLevelsPerStYearBySchAvaiLevelsPerYearID( _CurrentLevelsPerYear.ID);
}
protected override void CreateCommands()
{
SaveCommand = new RelayCommand(o =>
{
Save();
}
, o => Valdite());
CanselCommand = new DelegateCommand(() =>
{
if (Closed != null)
{
_CurrentLevelsPerYear = null;
Closed(_CurrentLevelsPerYear);
}
}
, () => true);
}
private void Save()
{
SchAvaiLevelsPerYear a = null;
string masseg = "";
if (Valdite())
{
a = _allSchAvaiLevelsPerYear.FirstOrDefault(i => i.ID != CurrentLevelsPerYear.ID && i.StageLevelID == _CurrentLevelsPerYear.StageLevelID);
if (a == null)
{
_CurrentLevelsPerYear.CoursCount = _AllCoursesLevelsPerStYear.Where(cc=>cc.Avalible).Count();
_CurrentLevelsPerYear.UserID = Session.SessionData.CurrentUser.UserID;
_CurrentLevelsPerYear.ID = _Repository.SaveSchAvaiLevelsPerYear(_CurrentLevelsPerYear);
CoursesLevelsPerStYear v;
foreach (CoursesLevelsPerStYear c in _AllCoursesLevelsPerStYear)
{
if (_isnew)
c.SALByYearID = _CurrentLevelsPerYear.ID;
c.UserID = Session.SessionData.CurrentUser.UserID;
v = (CoursesLevelsPerStYear)MyDataAccessTools.Clone<CoursesLevelsPerStYear>(c);
c.ID= _Repository.SaveCoursesLevelsPerStYearDirctliy(v);
}
///// the error massage aaper her when i use break point to know what are the changes that have been done
_CurrentLevelsPerYear.CoursesLevelsPerStYears = _AllCoursesLevelsPerStYear
//////
/////
}
else
masseg = "يوجد مستوى دراسي مماثل";
}
if (string.IsNullOrWhiteSpace(masseg))
Closed(a);
else
ErrorMasseg = masseg;
}
private bool Valdite()
{
bool result = false;
if (_CurrentLevelsPerYear != null && _CurrentLevelsPerYear.StageLevelID>0 )
result = true;
return result;
}
public override void Reset()
{
}
public SchAvaiLevelsPerYear CurrentLevelsPerYear
{
get { return _CurrentLevelsPerYear; }
set
{
if (_CurrentLevelsPerYear != value)
{
_CurrentLevelsPerYear = value;
NotifyPropertyChanged("CurrentLevelsPerYear");
}
}
}
public ObservableCollection<StageLevel> AllStageLevel
{
get { return _AllStageLevel; }
set
{
if (_AllStageLevel != value)
{
_AllStageLevel = value;
NotifyPropertyChanged("AllStageLevel");
}
}
}
public StageLevel SelectrdStageLevel
{
get { return _SelectrdStageLevel; }
set
{
if (_SelectrdStageLevel != value)
{
_SelectrdStageLevel = value;
NotifyPropertyChanged("SelectrdStageLevel");
if (_isnew)
{
ObservableCollection<CoursesLevelsPerStYear> allcby = new ObservableCollection<CoursesLevelsPerStYear>();
CoursesLevelsPerStYear cby;
foreach (CoursesByLevel cbl in _SelectrdStageLevel.CoursesByLevels)
{
cby = new CoursesLevelsPerStYear() {StartDate = Session.SessionData.CurrentYear.StartDate, Avalible =true
, CoursByLevelID = cbl.ID , CoursesByLevel= cbl, UserID = Session.SessionData.CurrentUser.UserID,
MaxLecturePerWeak = cbl.MaxLecturePerWeak,MinLecturePerWeak = cbl.MinLecturePerWeak,
SchAvaiLevelsPerYear = _CurrentLevelsPerYear
};
allcby.Add(cby);
}
AllCoursesLevelsPerStYear = allcby;
}
}
}
}
public ObservableCollection<CoursesLevelsPerStYear> AllCoursesLevelsPerStYear
{
get { return _AllCoursesLevelsPerStYear; }
set
{
if (_AllCoursesLevelsPerStYear != value)
{
_AllCoursesLevelsPerStYear = value;
NotifyPropertyChanged("AllCoursesLevelsPerStYear");
}
}
}
public bool IsEnabled
{
get { return _IsEnabled; }
set
{
if (_IsEnabled != value)
{
_IsEnabled = value;
NotifyPropertyChanged("IsEnabled");
}
}
}
public string ErrorMasseg
{
get { return errorMasseg; }
private set
{
if (value != errorMasseg)
{
errorMasseg = value;
NotifyPropertyChanged("ErrorMasseg");
}
}
}
public event Action<SchAvaiLevelsPerYear> Closed;
public ICommand SaveCommand
{
private set;
get;
}
public DelegateCommand CanselCommand
{
private set;
get;
}
}
}
这个实体
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Manual changes to this file may cause unexpected behavior in your application.
// Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace DataAccess
{
using System;
using System.Collections.ObjectModel;
public partial class SchAvaiLevelsPerYear : BaseModel
{
public SchAvaiLevelsPerYear()
{
this.CoursesLevelsPerStYears = new ObservableCollection<CoursesLevelsPerStYear>();
this.StduyYearLevelFrogs = new ObservableCollection<StduyYearLevelFrog>();
}
private int _iD;
public int ID
{
get { return _iD; }
set { SetProperty(ref _iD, value); }
}
private int _yearID;
public int YearID
{
get { return _yearID; }
set { SetProperty(ref _yearID, value); }
}
private int _stageLevelID;
public int StageLevelID
{
get { return _stageLevelID; }
set { SetProperty(ref _stageLevelID, value); }
}
private int _schoolID;
public int SchoolID
{
get { return _schoolID; }
set { SetProperty(ref _schoolID, value); }
}
private bool _avalible;
public bool Avalible
{
get { return _avalible; }
set { SetProperty(ref _avalible, value); }
}
private int _coursCount;
public int CoursCount
{
get { return _coursCount; }
set { SetProperty(ref _coursCount, value); }
}
private byte[] _timestamp;
public byte[] Timestamp
{
get { return _timestamp; }
set { SetProperty(ref _timestamp, value); }
}
private int _userID;
public int UserID
{
get { return _userID; }
set { SetProperty(ref _userID, value); }
}
public virtual Branch Branch { get; set; }
public virtual ObservableCollection<CoursesLevelsPerStYear> CoursesLevelsPerStYears { get; set; }
public virtual StageLevel StageLevel { get; set; }
public virtual StudyYear StudyYear { get; set; }
public virtual ObservableCollection<StduyYearLevelFrog> StduyYearLevelFrogs { get; set; }
}
}
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Manual changes to this file may cause unexpected behavior in your application.
// Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace DataAccess
{
using System;
using System.Collections.ObjectModel;
public partial class CoursesLevelsPerStYear : BaseModel
{
public CoursesLevelsPerStYear()
{
this.CourseGroups = new ObservableCollection<CourseGroup>();
this.Teachers = new ObservableCollection<Teacher>();
}
private int _iD;
public int ID
{
get { return _iD; }
set { SetProperty(ref _iD, value); }
}
private int _coursByLevelID;
public int CoursByLevelID
{
get { return _coursByLevelID; }
set { SetProperty(ref _coursByLevelID, value); }
}
private int _sALByYearID;
public int SALByYearID
{
get { return _sALByYearID; }
set { SetProperty(ref _sALByYearID, value); }
}
private int _maxLecturePerWeak;
public int MaxLecturePerWeak
{
get { return _maxLecturePerWeak; }
set { SetProperty(ref _maxLecturePerWeak, value); }
}
private int _minLecturePerWeak;
public int MinLecturePerWeak
{
get { return _minLecturePerWeak; }
set { SetProperty(ref _minLecturePerWeak, value); }
}
private bool _haveGroup;
public bool HaveGroup
{
get { return _haveGroup; }
set { SetProperty(ref _haveGroup, value); }
}
private bool _avalible;
public bool Avalible
{
get { return _avalible; }
set { SetProperty(ref _avalible, value); }
}
private Nullable<int> _holeID;
public Nullable<int> HoleID
{
get { return _holeID; }
set { SetProperty(ref _holeID, value); }
}
private bool _hasHole;
public bool HasHole
{
get { return _hasHole; }
set { SetProperty(ref _hasHole, value); }
}
private System.DateTime _startDate;
public System.DateTime StartDate
{
get { return _startDate; }
set { SetProperty(ref _startDate, value); }
}
private Nullable<System.DateTime> _stopDate;
public Nullable<System.DateTime> StopDate
{
get { return _stopDate; }
set { SetProperty(ref _stopDate, value); }
}
private byte[] _timestamp;
public byte[] Timestamp
{
get { return _timestamp; }
set { SetProperty(ref _timestamp, value); }
}
private int _userID;
public int UserID
{
get { return _userID; }
set { SetProperty(ref _userID, value); }
}
public virtual ObservableCollection<CourseGroup> CourseGroups { get; set; }
public virtual CoursesByLevel CoursesByLevel { get; set; }
public virtual Hole Hole { get; set; }
public virtual SchAvaiLevelsPerYear SchAvaiLevelsPerYear { get; set; }
public virtual ObservableCollection<Teacher> Teachers { get; set; }
}
}
namespace DataAccess
{
partial class CoursesLevelsPerStYear : BaseModel
{
private bool _CanEdit;
public bool CanEdit
{
get { return _CanEdit; }
set
{
SetProperty(ref _CanEdit, value);
}
}
private bool _EditMode;
public bool EditMode
{
get { return _EditMode; }
set
{
SetProperty(ref _EditMode, value);
}
}
string _EditButtonVisibility = "";
public string EditButtonVisibility
{
get
{
return _EditButtonVisibility;
}
set { SetProperty(ref _EditButtonVisibility, value); }
}
}
}
这个只有这样的问题的关系。是的，我忘了提到我使用this和this更改了实体框架的DBContext 我正在使用实体框架6.2
原谅我的英语我不是一位优秀的英国作家。