实体属性为空,即使使用值实体框架

因此出于某种原因,当我尝试执行db.SaveChanges时,它说属性Username不允许插入null值,但在使用调试器时不为null.项目Username属性中包含一个字符串…

public void fvAddUser_InsertItem()
{
    var item = new InventarioCiclico.xUtilizador();

    TryUpdateModel(item);

    if (ModelState.IsValid)
    {
        using (InventarioCiclicoContext db = new InventarioCiclicoContext())
        {
            if (db.xUtilizador.Any(u => u.Username == item.Username))
            {
                Page.ClientScript
                    .RegisterStartupScript(
                        this.GetType(),
                        "ShowToast",
                        "ShowToast('Erro','topCenter','error', 'Utilizador já exsiste.', '2000')",
                        true
                    );
            }
            else
            {
                xColaborador c = new xColaborador();
                c.Nome = (fvAddUser.FindControl("txtNome") as TextBox).Text;
                c.Email = (fvAddUser.FindControl("txtEmail") as TextBox).Text;
                item.xColaborador.Add(c);

                db.xUtilizador.Add(item);
                db.SaveChanges();
                Page.ClientScript
                    .RegisterStartupScript(
                        this.GetType(),
                        "ShowToast",
                        "ShowToast('OK', 'topCenter','success', 'Utilizador adicionado com sucesso.', '2000')",
                        true
                    );
            }
        }
    }
}

我首先使用数据库,这是xUtilizador类

public partial class xUtilizador
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
    public xUtilizador()
    {
        this.Activo = true;
        this.xAcesso = new HashSet<xAcesso>();
        this.xColaborador = new HashSet<xColaborador>();
    }

    public int UserID { get; set; }
    public string Username { get; set; }
    public bool Activo { get; set; }
    public Nullable<System.DateTime> UltimoAcesso { get; set; }

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public virtual ICollection<xAcesso> xAcesso { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public virtual ICollection<xColaborador> xColaborador { get; set; }
}

编辑

我还必须创建部分和元数据类以更新数据库中的默认值

 [MetadataType(typeof(Metadata.UtilizadorMetadata))]
    public partial class xUtilizador
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
        public bool Activo { get; set; }
    }

 public class UtilizadorMetadata
    {
        [StringLength(8)]
        [Display(Name="Username")]
        public string Username;

        [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
        public bool Active;
    }

编辑

另外我只是注意到由于某种原因,用户名StoreGeneratedPattern设置为Computed,并且我从未在数据库中给它任何默认值.

解决方法:

问题是在StoreGeneratedPattern的模型上将用户名设置为“已计算”.确保将其设置为none以在插入时不给出null异常.

标签：entity-framework-6,c
来源： https://codeday.me/bug/20191211/2105701.html