ASP.NET BoilerPlate: How to detach entity object from context? - aspnetboilerplate

Question

How to detach entity object from context?
Unable to get access to the context in my application service
How to clone a row using asp.net boilerplate?
e.g. I have row say row1 with primary key Id
I want to insert same row contents with new Id

Answer 1

You can access DbContext in repository (should not use DbContext in application service). Create custom repository, define some methods that you want to use in application service layer, see document here
To clone object, you can create copy method in the entity class or use AutoMapper.

Answer 2

1) You can inject IDbContextProvider<TDbContext> into your class and use it's GetDbContext method to get the DbContext.
2) If you have a DTO class which you use for saving your entity, then for cloning an entity, you can follow below steps:
Get original entity from database
Map it to your entity save dto (I assume it does not contain Id field)
Then map your dto to entity
Save your entity.
Thanks.

Answer 3

You can use newtonsoft serialization:
/// <summary>
/// Perform a deep Copy of the object, using Json as a serialisation method. NOTE: Private members are not cloned using this method.
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneJson<T>(this T source)
{
// Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
// initialize inner objects individually
// for example in default constructor some list property initialized with some values,
// but in 'source' these items are cleaned -
// without ObjectCreationHandling.Replace default constructor values will be added to result
var deserializeSettings = new JsonSerializerSettings {ObjectCreationHandling = ObjectCreationHandling.Replace};
return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(source), deserializeSettings);
}
Or you can use ObjectCopier
using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
/// <summary>
/// Reference Article http://www.codeproject.com/KB/tips/SerializedObjectCloner.aspx
/// Provides a method for performing a deep copy of an object.
/// Binary Serialization is used to perform the copy.
/// </summary>
public static class ObjectCopier
{
/// <summary>
/// Perform a deep Copy of the object.
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T Clone<T>(T source)
{
if (!typeof(T).IsSerializable)
{
throw new ArgumentException("The type must be serializable.", "source");
}
// Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
IFormatter formatter = new BinaryFormatter();
Stream stream = new MemoryStream();
using (stream)
{
formatter.Serialize(stream, source);
stream.Seek(0, SeekOrigin.Begin);
return (T)formatter.Deserialize(stream);
}
}
}