controller中edit方法的transfer参数中的DateTime总是01.01.0001 00:00:00 asp.net mvc5

Question

I a problem in the transfer parameter in the Edit Method "issue".

In Issue the CreatedDate and UpdatedDate is always {01.01.0001 00:00:00}.

The parameter Id, Title and Description is always correct.

My Controller:

public ActionResult Edit([Bind(Include = "Id,Title,Description")] Issue issue)
{
    if (ModelState.IsValid)
    {
        db.Entry(issue).State = EntityState.Modified;
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    return View(issue);
}

My Model:

public class Issue : BaseEntity
{
    public int Id { get; set; }

    [Required(ErrorMessage = "Required")]
    public string Title { get; set; }
    
    [AllowHtml]
    [Required(ErrorMessage = "Required")]
    [DataType(DataType.MultilineText)]
    public string Description { get; set; }

}

public class BaseEntity
{
    public DateTime CreatedDate { get; set; }
    public DateTime UpdatedDate { get; set; }
}

I can unfortunately can not debug from where the "issue" parameter comes from.

From where the transfer parameter "Issue issue" in the Edit method comes from and why are all DateTimes always {01.01.0001 00:00:00}?

When I create the first time a issue entity I add the DateTimme in the SaveChanges() Method with the following modification in my DBContext:

public override int SaveChanges()
{
    var entries = ChangeTracker
        .Entries()
        .Where(e => e.Entity is BaseEntity && (
                e.State == EntityState.Added
                || e.State == EntityState.Modified));

    foreach (var entityEntry in entries)
    {
        ((BaseEntity)entityEntry.Entity).UpdatedDate = DateTime.UtcNow;

        if (entityEntry.State == EntityState.Added)
        {
            ((BaseEntity)entityEntry.Entity).CreatedDate = DateTime.UtcNow;
        }
    }

    return base.SaveChanges();
}

And the SaveChanges() works without problem. When I create the issue entity the first time the DateTime has the correct value and I can also see it in the Detail View.

Answer 1

Change your edit code to this

var exist =  d.Set<Issue>().FindAsync(issue.Id);
 
if (exist == null)
                {
//ErrorMessage = "Can't find item to update";
                    
}
else{

    db.Entry(exist).CurrentValues.SetValues(issue);
    var result = await db.SaveChanges(); // result should be  > 0
}