Visual Basic

Dim t a type
Dim s  as string = "MyProg1.Child1,MyProg1,Version=1.0.0, Culture=neutral,PublicKeyToken=null"
t=System.Type.GetType(s)

CTypeDynamic(Element,Child1)

Dim t a type
Dim s  as string = "MyProg1.Child1,MyProg1,Version=1.0.0, Culture=neutral,PublicKeyToken=null"
t=System.Type.GetType(s)
CtypeDynamic(Element,t)

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

Additional information: The entity type Object is not part of the model for the current context.

Dim element = CType(Enumerable.ElementAt(CallByName(MyObj1, "Child1", CallType.Get), k), Child1)

Dim element = CTypeDynamic(Enumerable.ElementAt(CallByName(MyObj1, "Child1", CallType.Get), k), Type.GetType("MyProg1.Child1,MyProg1,Version=1.0.0, Culture=neutral,PublicKeyToken=null"))

Dim el = Enumerable.ElementAt(CallByName(MyClass, "Children", CallType.Get), 1)

REM 1
Dim el1 = CType(el, ChildClass)
Dim el1copy = CopyEntity(el1)   REM works. (el1copy is of type ChildClass)

REM 2
Dim el2 = CTypeDynamic(Of ChildClass)(el)
Dim el2copy = CopyEntity(el2)   REM works. (el2copy is of type ChildClass)

REM 3
Dim el3 = CTypeDynamic(el, GetType(ChildClass))
Dim el3copy = CopyEntity(el3)   REM doesn't work. (el3copy is of type Object)

class ChildClass
{ }

class MyClass
{
    public ICollection<ChildClass> Children { get; set; }

    public MyClass()
    {
        Children = new HashSet<ChildClass>() { new ChildClass() };
    }
}

T CopyEntity<T>(T entity)
    where T : class, new()
{
    T copy = new T();
    // actual copying omitted here
    // for testing only the return type matters
    return copy;
}

void Test()
{
    MyClass myClass = new MyClass();
    dynamic children = typeof(MyClass).GetProperty("Children").GetValue(myClass);
    dynamic child = Enumerable.ElementAt(children, 0);
    dynamic copy = CopyEntity(child);
    // copy is of type ChildClass
}

Class ChildClass
End Class

Class [MyClass]
    Public Property Children() As ICollection(Of ChildClass)
        Get
            Return m_Children
        End Get
        Set
            m_Children = Value
        End Set
    End Property
    Private m_Children As ICollection(Of ChildClass)

    Public Sub New()
        Children = New HashSet(Of ChildClass)() From { _
            New ChildClass() _
        }
    End Sub
End Class

Private Function CopyEntity(Of T As {Class, New})(entity As T) As T
    Dim copy As New T()
    ' actual copying omitted here
    ' for testing only the return type matters
    Return copy
End Function

Private Sub Test()
    Dim [myClass] As New [MyClass]()
    Dim children As dynamic = GetType([MyClass]).GetProperty("Children").GetValue([myClass])
    Dim child As dynamic = Enumerable.ElementAt(children, 0)
    Dim copy As dynamic = CopyEntity(child)
    ' copy is of type ChildClass
End Sub

Dim en = ctx.Entry(clone)

dilkonika wrote:

and this code is not using CTypeDynamic.

Public Class ChildClass
End Class

Public Class SomeClass
    Public Property Children As ICollection(Of ChildClass) = New HashSet(Of ChildClass)
End Class

Public Function CopyEntity(Of T As {Class, New})(entity As T) As T
    Dim clone As New T()
    Return clone
End Function

Sub Main()
    Dim someClass = New SomeClass
    someClass.Children.Add(New ChildClass)

    Dim el = Enumerable.ElementAt(CallByName(someClass, "Children", CallType.Get), 0)

    Dim elcopy = CopyEntity(el)   REM without CTypeDynamic. doesn't work. (elcopy is Object)

    Dim el1 = CType(el, ChildClass)
    Dim el1copy = CopyEntity(el1) REM works (el1copy is ChildClass)

    Dim el2 = CTypeDynamic(Of ChildClass)(el)
    Dim el2copy = CopyEntity(el2) REM works (el2copy is ChildClass)

    Dim el3 = CTypeDynamic(el, GetType(ChildClass))
    Dim el3copy = CopyEntity(el3) REM doesn't work (el3copy is Object)
End Sub

Quote:

and on my vb.net code , the error came up on the line :
Dim en = ctx.Entry(clone)
and you don't have a such line in your code.

dilkonika wrote:

Also I try to implement your version with reflection , but I can't make it work on vb.net ? can you provide some more
help ?

class Program
{
    class ChildClass
    { }

    class SomeClass
    {
        public ICollection<ChildClass> Children { get; set; }

        public SomeClass()
        {
            Children = new HashSet<ChildClass>() { new ChildClass() };
        }
    }

    public static T CopyEntity<T>(T entity)
        where T : class, new()
    {
        T copy = new T();
        return copy;
    }

    static void Main(string[] args)
    {
        SomeClass someClass = new SomeClass();

        dynamic children = typeof(SomeClass).GetProperty("Children").GetValue(someClass);
        object child = Enumerable.ElementAt(children, 0);

        // if CopyEntity would be not a static method, BindingFlags.Instance
        // would have to be used, instead of BindingFlags.Static 
        MethodInfo mi = typeof(Program).GetMethod("CopyEntity", BindingFlags.Static | BindingFlags.Public);
        mi = mi.MakeGenericMethod(new Type[] { /* +typeof(YourContext) */ child.GetType() /* +typeof(bool) */ });

        // if CopyEntity would be not a static method, the first argument
        // to Invoke would have to be the class-instance on which to invoke
        // CopyEntity, instead of null
        object clone = mi.Invoke(null, new object[] { /* +ctx */ child /* +copyKeys */ });
        // -> clone is of type ChildClass
    }
}

Dim clone as New(T)

Dim clone = Activator.CreateInstance(entity.GetType())

dilkonika wrote:

Dim clone = Activator.CreateInstance(entity.GetType())

dilkonika wrote:

Thank you for your help.

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

Partial Public Class Child_list
    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 

• Move the SetValue(..)-line back to where it was.
• Put an EdmScalarPropertyAttribute on the name-property of the Myobject-class and on all properties of the Child_list-class (except id and ParentID) like so:
  VB

  <EdmScalarProperty()>
  Public property name as string

• In CloneEntityHelper(..), change the string "EntityCollection`1" to "ICollection`1".
• If you want to have children of children copied (to an arbitrary depth), set the Children-property of your IncludeEntity-instance to the same IncludeEntity-instance.
• If you have to initialize id yourself, you will have to set it for Myobjects, Child_lists and potentially further nested objects, after the call to CloneEntity(..).
• Because of the self-referencing through ParentID you will have to set ParentID for all children (and potentially children of children) to their respective parent's id after the call to CloneEntity(..) (in any case).