Visual Basic

Cloning by Reflection uses Activator.CreateInstance to create a new object of the same type, then performs a shallow copy of each field using Reflection. The advantage of this method is it's automated and does not need to be adjusted when members are added or removed from the object. Also, it can be written to provide a deep copy. The disadvantage is it uses Reflection, which is slower and not allowed in partial trust environments.

dilkonika wrote:

On your link in the clone with reflection section , contains just words.

<pre>  <Extension> _
    Public Sub CopyTo(Of T)(copyFrom As T, copyTo__1 As T, copyParentProperties As Boolean)
        Dim props As PropertyInfo()
        If copyParentProperties Then
            props = GetType(T).GetProperties()
        Else
            props = GetType(T).GetProperties(BindingFlags.[Public] Or BindingFlags.Instance Or BindingFlags.DeclaredOnly)
        End If
        Dim i As Integer = 0
        While i < props.Length
            Dim propertyValue = copyFrom.[GetType]().GetProperty(props(i).Name).GetValue(copyFrom, Nothing)
            copyTo__1.[GetType]().GetProperty(props(i).Name).SetValue(copyTo__1, propertyValue, Nothing)
            System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
        End While
    End Sub

newitm = New Myobject
currentobj.CopyTo(newitm, False)
context.MyObjects.Add(Newitm)
context.savechanges

An unhandled exception of type 'System.InvalidOperationException' occurred in System.Core.dll

Additional information: Collection was modified; enumeration operation may not execute.

dilkonika wrote:

there are many articles on internet that suggest avoid ICloneable because of Shallow/Deep confusion.

dilkonika wrote:

An unhandled exception of type 'System.InvalidOperationException' occurred in System.Core.dll
Additional information: Collection was modified; enumeration operation may not execute.

newitm = New Myobject
currentobj.CopyTo(newitm, False)
context.MyObjects.Add(Newitm)
context.savechanges

newitm = New Myobject
context.MyObjects.Add(newitm)
currentobj.CopyTo(newitm, False)
context.savechanges

Partial Public Class Myobject
  Public Property id As Integer
  Public property name as string
  Public Overridable Property chld As ICollection(Of chld) = New HashSet(Of chld) 
 End Class

Partial Public Class chld
    Public Property id As Integer
    Public Property date1 as DateTime
    Public Property quantity as Integer
    Public Property ParentID as integer
    Public Overridable Property MyObj1 As MyObject
End Class 

An unhandled exception of type 'System.Runtime.Serialization.SerializationException' occurred in System.Runtime.Serialization.dll

Additional information: Type 'System.Data.Entity.DynamicProxies.MyObject_F2FFE64DA472EB2B2BDF7E143DE887D3845AD9D1731FD3107937062AC0C2E4BB' with data contract name 'MyObject_F2FFE64DA472EB2B2BDF7E143DE887D3845AD9D1731FD3107937062AC0C2E4BB:http://schemas.datacontract.org/2004/07/System.Data.Entity.DynamicProxies' is not expected. Consider using a DataContractResolver or add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.

Imports System.Data.Entity.Core.Objects.DataClasses
Imports System.Runtime.Serialization
Imports System.IO
Imports System.Runtime.CompilerServices
Imports System.Data.Objects

Module Extensions
    <Extension>
    Public Function Clone(Of T)(source As T) As T
        Dim ser = New DataContractSerializer(GetType(T))
        Using stream = New MemoryStream()
            ser.WriteObject(stream, source)
            stream.Seek(0, SeekOrigin.Begin)
            Return CType(ser.ReadObject(stream), T)
        End Using
    End Function
End Module

Dim litm, newitm as MyObject
        For Each litm In itemlist
            newitm = litm.Clone()
        ...
        Next

Myob1list = (From t in context.ob1s.Include("chld")
             Select t).ToList()

dilkonika wrote:

Sorry , but I'm using lazyloading.
and I've read that these proxy objects , are related with using of lazyloading.

dilkonika wrote:

So , why all other actions that I do with my objects works without problems, and this Clone action produce errors ?

dilkonika wrote:

Sorry , but I'm using lazyloading.