基本上问题是重复的，但我需要解决方案
后端：C＃ - asp.net MVC5 - EF6.13框架 Visual studuio：2013 SQL SERVER：2008
当我想通过两个类将数据插入数据库时，会生成消息：
(An exception of type 'System.NullReferenceException' occurred in BusinessErpMVC.dll but was not handled in user code
Additional information: La référence d'objet n'est pas définie à une instance d'un objet.)
知道这两个类都有一个懒惰的连接，我现在会告诉你我的calsses：
CommandeClt类
public partial class CommandeClt
{
public CommandeClt()
{
this.CommandeClt_Ligne = new HashSet<CommandeClt_Ligne>();
}
public int CommandeCltID { get; set; }
[Display(Name = "Code Cmd")]
public int Cd_CommandeClt { get; set; }
[Display(Name = "Ref Cmd")]
public string Ref_CommandeClt { get; set; }
[Display(Name = "Date Cmd")]
[DataType(DataType.Date)]
public Nullable<System.DateTime> Date_CommandeClt { get; set; }
[Display(Name = "Societe")]
public byte Id_Societe { get; set; }
public string Nom_Societe { get; set; }
public string Adresse_Societe { get; set; }
public string CodePostal_Societe { get; set; }
[Display(Name = "Client")]
public int Id_CltOrigine { get; set; }
public string Nom_CltOrigine { get; set; }
public string Adresse_CltOrigine { get; set; }
public string CodePostal_CltOrigine { get; set; }
public Nullable<int> Id_CltLivre { get; set; }
public string Nom_CltLivre { get; set; }
public string Adresse_CltLivre { get; set; }
public string CodePostal_CltLivre { get; set; }
public Nullable<int> Id_CltFacture { get; set; }
public string Nom_CltFacture { get; set; }
public string Adresse_CltFacture { get; set; }
public string CodePostal_CltFacture { get; set; }
public int Id_Devise { get; set; }
public decimal Taux_Devise { get; set; }
public Nullable<byte> Id_ModeLivraison { get; set; }
public Nullable<byte> Id_ModeExpedition { get; set; }
public Nullable<byte> Id_ModeReglement { get; set; }
public Nullable<System.DateTime> Date_Livraison { get; set; }
public Nullable<System.DateTime> Date_Expedition { get; set; }
public Nullable<decimal> Taux_Remise { get; set; }
public Nullable<decimal> Montant_Remise { get; set; }
public Nullable<decimal> Taux_Escompte { get; set; }
public Nullable<decimal> Montant_Escompte { get; set; }
public Nullable<decimal> Montant_Net_HT { get; set; }
public Nullable<decimal> Montant_TVA { get; set; }
public Nullable<decimal> Montant_TTC { get; set; }
public Nullable<decimal> Acompte { get; set; }
public Nullable<decimal> Montant_Net_Apayer { get; set; }
public Nullable<decimal> Poids_Total { get; set; }
public Nullable<decimal> Volume_Total { get; set; }
public Nullable<decimal> Metrage_Total { get; set; }
public Nullable<bool> IsActual { get; set; }
public string Commentaire { get; set; }
public System.DateTime Date_Creation { get; set; }
public Nullable<System.DateTime> Date_Update { get; set; }
public Nullable<System.DateTime> Date_Validation { get; set; }
public Nullable<int> Id_Creator { get; set; }
public Nullable<int> Id_Updator { get; set; }
public Nullable<int> Id_Validator { get; set; }
public Nullable<byte> Etat_CommandeClt { get; set; }
public virtual ICollection<CommandeClt_Ligne> CommandeClt_Ligne { get; set; }
[ForeignKey("Id_Societe")]
public virtual Societe Societe { get; set; }
[ForeignKey("Id_CltOrigine")]
[InverseProperty("Id_ClientOrigine")]
public virtual Partenaire ClientOrigine { get; set; }
[ForeignKey("Id_CltLivre")]
[InverseProperty("Id_CltLivre")]
public virtual Partenaire CltLivre { get; set; }
[ForeignKey("Id_CltFacture")]
[InverseProperty("Id_CltFacture")]
public virtual Partenaire CltFacture { get; set; }
[ForeignKey("Id_ModeLivraison")]
public virtual ModeLivraison ModeLivraison { get; set; }
}
CommandeClt_Ligne class
public partial class CommandeClt_Ligne
{
public int CommandeCltID { get; set; }
public byte Id_CommandeClt_Ligne { get; set; }
public int Id_Article { get; set; }
public string Lib_Article { get; set; }
public Nullable<decimal> Qte_Demandee { get; set; }
public Nullable<decimal> Qte_Livree { get; set; }
public Nullable<decimal> Qte_ALivrer { get; set; }
public Nullable<decimal> Qte_Poids { get; set; }
public Nullable<decimal> Qte_Volume { get; set; }
public Nullable<decimal> Qte_Metrage { get; set; }
public Nullable<byte> Id_Unite { get; set; }
public Nullable<decimal> Prix_HT { get; set; }
public Nullable<decimal> Taux_Remise { get; set; }
public Nullable<byte> Id_TVA { get; set; }
public Nullable<decimal> Taux_TVA { get; set; }
public Nullable<System.DateTime> Date_Livraison { get; set; }
public Nullable<int> Id_DevisClt { get; set; }
public Nullable<byte> Id_DevisClt_Ligne { get; set; }
public Nullable<int> Id_CommandeOuverteClt { get; set; }
public Nullable<byte> Id_CommandeOuverteClt_Ligne { get; set; }
public string Commentaire { get; set; }
public byte Etat_CommandeClt_Ligne { get; set; }
public virtual CommandeClt CommandeClt { get; set; }
}
C＃代码：
[HttpPost]
public ActionResult Create(CommandeClt commandeclt)
{
try
{
ViewBag.SelectedSociete = new SelectList(MetiersRepository.SocieteAll(), "Id_Societe", "Cd_Societe");
ViewBag.SelectedClient = new SelectList(MetiersRepository.ClientAll(), "Id_Partenaire", "Cd_Partenaire");
ViewBag.SelectedDevise = new SelectList(MetiersRepository.DeviseAll(), "Id_Devise", "Lib_Devise");
ViewBag.SelectedModeLivraison = new SelectList(MetiersRepository.ModeLivraisonAll(), "Id_ModeLivraison", "Lib_ModeLivraison");
ViewBag.SelectedModeExpedition = new SelectList(MetiersRepository.ModeExpeditionAll(), "Id_ModeExpedition", "Lib_ModeExpedition");
if (ModelState.IsValid)
{
dbMng.CommandeClts.Add(commandeclt);
dbMng.SaveChanges();
return RedirectToAction("Index");
}
}
catch (DataException /* dex */)
{
//Log the error (uncomment dex variable name after DataException and add a line here to write a log.
ModelState.AddModelError(string.Empty, "Unable to save changes. Try again, and if the problem persists contact your system administrator.");
}
return View(commandeclt);
}
这是更多解释的图片
图片1：
非常感谢