C# ASP MVC代码首先处理datetime计算列
我已经阅读了许多示例,试图找出如何在通过C# ASP MVC代码首先处理datetime计算列,c#,asp.net,asp.net-mvc,code-first,unit-of-work,C#,Asp.net,Asp.net Mvc,Code First,Unit Of Work,我已经阅读了许多示例,试图找出如何在通过unitOfWork和存储库模式保存更改时自动设置每个实体的CreatedDate值 因此,我所拥有的是简单的POCO: public class Partners:IAutoGenerateDateFields { [Key] public int PartnerId { get; set; } public string PartnerCode { get; set; }
unitOfWork
和存储库模式保存更改时自动设置每个实体的CreatedDate
值
因此,我所拥有的是简单的POCO
:
public class Partners:IAutoGenerateDateFields
{
[Key]
public int PartnerId { get; set; }
public string PartnerCode { get; set; }
public string PartnerName { get; set; }
public string CompanyName { get; set; }
public string City { get; set; }
public string Address { get; set; }
public string Phone { get; set; }
public string Fax { get; set; }
public string TaxId { get; set; }
public int PartnerTypeId { get; set; }
public int PartnerStateId { get; set; }
public int LocationId { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public DateTime CreatedDate { get; set; }
// [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
// public DateTime ModifiedDate { get;set;}
public virtual Locations Location { get; set; }
}
此类实现了IAutoGenerateDateFields
接口:
interface IAutoGenerateDateFields
{
DateTime CreatedDate { get; set; }
// DateTime ModifiedDate { get; set; }
}
最后,在我的unitOfWork
类中,我检查添加/修改的实体是否实现了上述接口,并将CreatedDate
值设置为当前日期:
public void Save() {
context.ChangeTracker.DetectChanges();
var added = context.ChangeTracker.Entries()
.Where(t => t.State == EntityState.Added)
.Select(t => t.Entity).ToArray();
foreach (var entity in added) {
if (entity is IAutoGenerateDateFields) {
var track = entity as IAutoGenerateDateFields;
track.CreatedDate = DateTime.Now;
}
}
var modified = context.ChangeTracker.Entries()
.Where(t => t.State == EntityState.Modified)
.Select(t => t.Entity).ToArray();
foreach (var entity in modified) {
if (entity is IAutoGenerateDateFields) {
var track = entity as IAutoGenerateDateFields;
track.CreatedDate = DateTime.Now;
}
}
context.SaveChanges();
}
但是每次我点击savechanges
时,我都会得到一个错误,CreatedDate
不能为空。因此,实体不会设置为当前日期
这里缺少什么?删除[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
属性,因为您在代码中生成了值
我昨天基本上做了同样的事情,下面的代码运行良好:
var pendingChanges = GetContext().ChangeTracker.Entries<T>().Select(e => e.Entity).ToList();
foreach (var entity in pendingChanges)
{
entity.DateModified = DateTime.Now
}
var pendingChanges=GetContext().ChangeTracker.Entries().Select(e=>e.Entity.ToList();
foreach(待处理变更中的var实体)
{
entity.DateModified=DateTime.Now
}
删除[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
属性,因为您在代码中生成了值
我昨天基本上做了同样的事情,下面的代码运行良好:
var pendingChanges = GetContext().ChangeTracker.Entries<T>().Select(e => e.Entity).ToList();
foreach (var entity in pendingChanges)
{
entity.DateModified = DateTime.Now
}
var pendingChanges=GetContext().ChangeTracker.Entries().Select(e=>e.Entity.ToList();
foreach(待处理变更中的var实体)
{
entity.DateModified=DateTime.Now
}