Reputation: 14937
I have tried this tutorial, but it's not working for me (Link), My objective is update just one field of my Entity... no other fields. I'm testing EntityFramework, and I would like to check if I can to do an automapper of a DTO and after update just one field.
I have tried this:
MyContext db = new MyContext();
MyClass sampleModel = new MyClass();
sampleModel.IdMyClass = "1d1ba1f2-8c08-c334-5486-08d16fecc6e3"; //GUID
sampleModel.ModificationDate = DateTime.Now;
db.MyClass.Attach(sampleModel);
db.Entry(sampleModel).Property(x => x.ModificationDate).IsModified = true;
db.SaveChanges();
MyClass Class
public partial class MyClass
{
public string IdMyClass { get; set; }
public string Name { get; set; }
public System.DateTime ModificationDate { get; set; }
public virtual ICollection<OtherClass> OtherClass{ get; set; }
}
MyClassMap
public MyClassMap() : EntityTypeConfiguration<MyClass>
{
//Primary Key
this.HasKey(t => t.IdMyClass);
//Properties
this.Property(t => t.Name)
.IsRequired()
.HasMaxLength(256);
// Table & Column Mappings
this.ToTable("MyClass");
this.Property(t => t.IdMyClass).HasColumnName("IdMyClass");
this.Property(t => t.Name).HasColumnName("Name");
this.Property(t => t.ModificationDate).HasColumnName("ModificationDate");
}
Where is my problem??
Error details, It happens in db.SaveChanges()
An exception of type 'System.Data.Entity.Validation.DbEntityValidationException' occurred in EntityFramework.dll but was not handled in user code
Additional information: Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.
EntityValidationErrors is empty...
Upvotes: 3
Views: 3589
Reputation: 334
You can define which properties will be updated with something like this:
MyContext db = new MyContext();
MyClass sampleModel = new MyClass();
sampleModel.IdMyClass = "1d1ba1f2-8c08-c334-5486-08d16fecc6e3"; //GUID
sampleModel.ModificationDate = DateTime.Now;
sampleModel.Name=string.Empty; //should not be needed
db.MyClass.Attach(sampleModel);
var entry=db.Entry(sampleModel);
entry.State = EntityState.Modified;
var excluded = new string[] { "Name" };
foreach (var name in excluded)
{
entry.Property(name).IsModified = false;
}
db.SaveChanges();
Ok so here is my version of your code. The classes
public partial class MyClass
{
public string IdMyClass { get; set; }
public string Name { get; set; }
public System.DateTime ModificationDate { get; set; }
public ICollection<OtherClass> OtherClass { get; set; }
}
public partial class OtherClass
{
public int Id { get; set; }
public string Stuff { get; set; }
}
public class MyContext : DbContext
{
public MyContext()
: base("MyContextDb")
{
}
public DbSet<MyClass> MyClasses { get; set; }
public DbSet<OtherClass> OtherClasses { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<MyClass>().ToTable("MyClass");
modelBuilder.Entity<MyClass>()
.HasKey(t => t.IdMyClass)
.Property(t => t.Name)
.IsRequired()
.HasMaxLength(256);
modelBuilder.Entity<MyClass>().Property(t => t.IdMyClass).HasColumnName("IdMyClass");
modelBuilder.Entity<MyClass>().Property(t => t.Name).HasColumnName("Name");
modelBuilder.Entity<MyClass>().Property(t => t.ModificationDate).HasColumnName("ModificationDate");
}
}
A simple console program to test the result
class Program
{
static void Main(string[] args)
{
MyContext db = null; ;
try
{
db = new MyContext();
Foo(db);
Console.WriteLine("Id\tDate\tName");
foreach(var c in db.MyClasses)
{
Console.WriteLine("{0}\t{1}\t{2}",c.IdMyClass,c.ModificationDate,c.Name);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (db != null)
{
db.Dispose();
}
}
Console.ReadLine();
}
static void Foo(MyContext db)
{
var sampleModel = new MyClass();
sampleModel.IdMyClass = "1d1ba1f2-8c08-c334-5486-08d16fecc6e3"; //GUID
sampleModel.ModificationDate = DateTime.Now;
sampleModel.Name = string.Empty; //should not be needed
db.MyClasses.Attach(sampleModel);
var entry = db.Entry(sampleModel);
entry.State = EntityState.Modified;
var excluded = new string[] { "Name" };
foreach (var name in excluded)
{
entry.Property(name).IsModified = false;
}
db.SaveChanges();
}
}
Hope that helps.
Upvotes: 4