public static void Main()
{
#region RegisterDiagnosticListener
DiagnosticListener.AllListeners.Subscribe(new DiagnosticObserver());
#endregion
using (var context = new BlogsContext())
{
context.Database.EnsureDeleted();
context.Database.EnsureCreated();
context.Add(
new Blog
{
Name = "EF Blog",
Posts =
{
new Post {
Title = "EF Core 3.1!"
},
new Post {
Title = "EF Core 5.0!"
}
}
});
context.SaveChanges();
}
using (var context = new BlogsContext())
{
var blog = context.Blogs.Include(e => e.Posts).Single();
blog.Name = "EF Core Blog";
context.Remove(blog.Posts.First());
blog.Posts.Add(new Post {
Title = "EF Core 6.0!"
});
context.SaveChanges();
}
#endregion
}
public static void Main()
{
#region Demonstration
using (var context = new BlogsContext())
{
context.Database.EnsureDeleted();
context.Database.EnsureCreated();
context.Add(
new Blog
{
Id = 1,
Name = "EF Blog",
Posts =
{
new Post {
Id = 1, Title = "EF Core 3.1!"
},
new Post {
Id = 2, Title = "EF Core 5.0!"
}
}
});
context.SaveChanges();
}
using (var context = new BlogsContext())
{
var blog = context.Blogs.Include(e => e.Posts).Single();
blog.Name = "EF Core Blog";
context.Remove(blog.Posts.First());
blog.Posts.Add(new Post {
Id = 3, Title = "EF Core 6.0!"
});
context.SaveChanges();
}
#endregion
}
public static void Using_DbSet_Local_to_query_tracked_entities_2()
{
Console.WriteLine($">>>> Sample: {nameof(Using_DbSet_Local_to_query_tracked_entities_2)}");
Console.WriteLine();
Helpers.RecreateCleanDatabase();
Helpers.PopulateDatabase();
#region Using_DbSet_Local_to_query_tracked_entities_2
using var context = new BlogsContext();
var posts = context.Posts.Include(e => e.Blog).ToList();
Console.WriteLine("Local view after loading posts:");
foreach (var post in context.Posts.Local)
{
Console.WriteLine($" Post: {post.Title}");
}
context.Remove(posts[1]);
context.Add(
new Post
{
Title = "What’s next for System.Text.Json?",
Content = ".NET 5.0 was released recently and has come with many...",
Blog = posts[0].Blog
});
Console.WriteLine("Local view after adding and deleting posts:");
foreach (var post in context.Posts.Local)
{
Console.WriteLine($" Post: {post.Title}");
}
#endregion
Console.WriteLine();
}
public static async Task Main()
{
await CreateDatabases();
#region Program
// Insert, update, and delete some entities
using (var context = new BlogsContext())
{
context.Add(
new Blog {
Name = "EF Blog", Posts = { new Post {
Title = "EF Core 3.1!"
}, new Post{
Title = "EF Core 5.0!"
} }
});
await context.SaveChangesAsync();
}
using (var context = new BlogsContext())
{
var blog = context.Blogs.Include(e => e.Posts).Single();
blog.Name = "EF Core Blog";
context.Remove(blog.Posts.First());
blog.Posts.Add(new Post {
Title = "EF Core 6.0!"
});
context.SaveChanges();
}
// Do an insert that will fail
using (var context = new BlogsContext())
{
try
{
context.Add(new Post {
Id = 3, Title = "EF Core 3.1!"
});
await context.SaveChangesAsync();
}
catch (DbUpdateException)
{
}
}
// Look at the audit trail
using (var context = new AuditContext("DataSource=audit.db"))
{
foreach (var audit in context.SaveChangesAudits.Include(e => e.Entities).ToList())
{
Console.WriteLine(
$"Audit {audit.AuditId} from {audit.StartTime} to {audit.EndTime} was{(audit.Succeeded ? "" : " not")} successful.");
foreach (var entity in audit.Entities)
{
Console.WriteLine($" {entity.AuditMessage}");
}
if (!audit.Succeeded)
{
Console.WriteLine($" Error: {audit.ErrorMessage}");
}
}
}
#endregion
}