VB.NET || How To Copy All Properties & Fields From One Object To Another Using VB.NET

November 22, 2020 admin No comments

The following is a module with functions which demonstrates how to copy all properties and fields from one object to another using VB.NET.

The function demonstrated on this page is a generic extension method which uses reflection to copy all the matching properties and fields from one object to another.

This function works on both structure and class object fields and properties.

The two objects do not have to be the same type. Only the matching properties and fields are copied.

1. Copy Properties & Fields

The example below demonstrates the use of ‘Utils.Objects.CopyPropsTo‘ to copy all the matching properties and fields from the source object to the destination object.





		
		
			1. Copy Properties & Fields
			
Visual Basic .NET
			
			' Copy Properties & Fields

Imports Utils.Objects

Public Class Part
    Public Property PartName As String
    Public Property PartId As Integer
End Class

Public Structure Part2
    Public Property PartName As String
    Public PartId As Integer
End Structure

' Declare source object
Dim part1 = New Part With {
    .PartName = "crank arm",
    .PartId = 1234
}

' Declare destination object
Dim part2 = New Part2

' Copy matching properties and fields to destination
part1.CopyPropsTo(part2)

' Display information
Debug.Print($"{part2.PartId} - {part2.PartName}")

' expected output:
'    1234 - crank arm
			
				
					
				
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						' Copy Properties & Fields
 
Imports Utils.Objects
 
Public Class Part
    Public Property PartName As String
    Public Property PartId As Integer
End Class
 
Public Structure Part2
    Public Property PartName As String
    Public PartId As Integer
End Structure
 
' Declare source object
Dim part1 = New Part With {
    .PartName = "crank arm",
    .PartId = 1234
}
 
' Declare destination object
Dim part2 = New Part2
 
' Copy matching properties and fields to destination
part1.CopyPropsTo(part2)
 
' Display information
Debug.Print($"{part2.PartId} - {part2.PartName}")
 
' expected output:
'    1234 - crank arm

2. Utils Namespace

The following is the Utils Namespace. Include this in your project to start using!





		
		
			Utils Namespace
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 22, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On

Namespace Global.Utils
    Namespace Objects
        Public Module modObjects
            ''' <summary>
            ''' Copies all the matching properties and fields from 'source' to 'destination'
            ''' </summary>
            ''' <param name="source">The source object to copy from</param>  
            ''' <param name="destination">The destination object to copy to</param>  
            <Runtime.CompilerServices.Extension()>
            Public Sub CopyPropsTo(Of T1, T2)(source As T1, ByRef destination As T2)
                Dim sourceMembers = GetMembers(source.GetType)
                Dim destinationMembers = GetMembers(destination.GetType)

                ' Copy data from source to destination
                For Each sourceMember In sourceMembers
                    If Not CanRead(sourceMember) Then
                        Continue For
                    End If
                    Dim destinationMember = destinationMembers.FirstOrDefault(Function(x) x.Name.ToLower = sourceMember.Name.ToLower)
                    If destinationMember Is Nothing _
                        OrElse Not CanWrite(destinationMember) Then
                        Continue For
                    End If
                    SetObjectValue(destination, destinationMember, GetMemberValue(source, sourceMember))
                Next
            End Sub

            Private Sub SetObjectValue(Of T)(ByRef obj As T, member As System.Reflection.MemberInfo, value As Object)
                ' Boxing method used for modifying structures
                Dim boxed = If(obj.GetType.IsValueType, CType(obj, Object), obj)
                SetMemberValue(boxed, member, value)
                obj = CType(boxed, T)
            End Sub

            Private Sub SetMemberValue(Of T)(ByRef obj As T, member As System.Reflection.MemberInfo, value As Object)
                If IsProperty(member) Then
                    Dim prop = CType(member, System.Reflection.PropertyInfo)
                    If prop.SetMethod IsNot Nothing Then
                        prop.SetValue(obj, value)
                    End If
                ElseIf IsField(member) Then
                    Dim field = CType(member, System.Reflection.FieldInfo)
                    field.SetValue(obj, value)
                End If
            End Sub

            Private Function GetMemberValue(obj As Object, member As System.Reflection.MemberInfo) As Object
                Dim result As Object = Nothing
                If IsProperty(member) Then
                    Dim prop = CType(member, System.Reflection.PropertyInfo)
                    result = prop.GetValue(obj, If(prop.GetIndexParameters.Count = 1, New Object() {Nothing}, Nothing))
                ElseIf IsField(member) Then
                    Dim field = CType(member, System.Reflection.FieldInfo)
                    result = field.GetValue(obj)
                End If
                Return result
            End Function

            Private Function CanWrite(member As System.Reflection.MemberInfo) As Boolean
                Return If(IsProperty(member), CType(member, System.Reflection.PropertyInfo).CanWrite, IsField(member))
            End Function

            Private Function CanRead(member As System.Reflection.MemberInfo) As Boolean
                Return If(IsProperty(member), CType(member, System.Reflection.PropertyInfo).CanRead, IsField(member))
            End Function

            Private Function IsProperty(member As System.Reflection.MemberInfo) As Boolean
                Return IsType(member.GetType, GetType(System.Reflection.PropertyInfo))
            End Function

            Private Function IsField(member As System.Reflection.MemberInfo) As Boolean
                Return IsType(member.GetType, GetType(System.Reflection.FieldInfo))
            End Function

            Private Function IsType(type As System.Type, targetType As System.Type) As Boolean
                Return type.Equals(targetType) OrElse type.IsSubclassOf(targetType)
            End Function

            Private Function GetMembers(type As System.Type) As List(Of System.Reflection.MemberInfo)
                Dim flags = System.Reflection.BindingFlags.Instance Or System.Reflection.BindingFlags.Public _
                    Or System.Reflection.BindingFlags.NonPublic
                Dim members = New List(Of System.Reflection.MemberInfo)
                members.AddRange(type.GetProperties(flags))
                members.AddRange(type.GetFields(flags))
                Return members
            End Function
        End Module
    End Namespace
End Namespace ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 22, 2020
'    Taken From: http://programmingnotes.org/
'    File: Utils.vb
'    Description: Handles general utility functions
' ============================================================================
Option Strict On
Option Explicit On
 
Namespace Global.Utils
    Namespace Objects
        Public Module modObjects
            ''' <summary>
            ''' Copies all the matching properties and fields from 'source' to 'destination'
            ''' </summary>
            ''' <param name="source">The source object to copy from</param>  
            ''' <param name="destination">The destination object to copy to</param>  
            <Runtime.CompilerServices.Extension()>
            Public Sub CopyPropsTo(Of T1, T2)(source As T1, ByRef destination As T2)
                Dim sourceMembers = GetMembers(source.GetType)
                Dim destinationMembers = GetMembers(destination.GetType)
 
                ' Copy data from source to destination
                For Each sourceMember In sourceMembers
                    If Not CanRead(sourceMember) Then
                        Continue For
                    End If
                    Dim destinationMember = destinationMembers.FirstOrDefault(Function(x) x.Name.ToLower = sourceMember.Name.ToLower)
                    If destinationMember Is Nothing _
                        OrElse Not CanWrite(destinationMember) Then
                        Continue For
                    End If
                    SetObjectValue(destination, destinationMember, GetMemberValue(source, sourceMember))
                Next
            End Sub
 
            Private Sub SetObjectValue(Of T)(ByRef obj As T, member As System.Reflection.MemberInfo, value As Object)
                ' Boxing method used for modifying structures
                Dim boxed = If(obj.GetType.IsValueType, CType(obj, Object), obj)
                SetMemberValue(boxed, member, value)
                obj = CType(boxed, T)
            End Sub
 
            Private Sub SetMemberValue(Of T)(ByRef obj As T, member As System.Reflection.MemberInfo, value As Object)
                If IsProperty(member) Then
                    Dim prop = CType(member, System.Reflection.PropertyInfo)
                    If prop.SetMethod IsNot Nothing Then
                        prop.SetValue(obj, value)
                    End If
                ElseIf IsField(member) Then
                    Dim field = CType(member, System.Reflection.FieldInfo)
                    field.SetValue(obj, value)
                End If
            End Sub
 
            Private Function GetMemberValue(obj As Object, member As System.Reflection.MemberInfo) As Object
                Dim result As Object = Nothing
                If IsProperty(member) Then
                    Dim prop = CType(member, System.Reflection.PropertyInfo)
                    result = prop.GetValue(obj, If(prop.GetIndexParameters.Count = 1, New Object() {Nothing}, Nothing))
                ElseIf IsField(member) Then
                    Dim field = CType(member, System.Reflection.FieldInfo)
                    result = field.GetValue(obj)
                End If
                Return result
            End Function
 
            Private Function CanWrite(member As System.Reflection.MemberInfo) As Boolean
                Return If(IsProperty(member), CType(member, System.Reflection.PropertyInfo).CanWrite, IsField(member))
            End Function
 
            Private Function CanRead(member As System.Reflection.MemberInfo) As Boolean
                Return If(IsProperty(member), CType(member, System.Reflection.PropertyInfo).CanRead, IsField(member))
            End Function
 
            Private Function IsProperty(member As System.Reflection.MemberInfo) As Boolean
                Return IsType(member.GetType, GetType(System.Reflection.PropertyInfo))
            End Function
 
            Private Function IsField(member As System.Reflection.MemberInfo) As Boolean
                Return IsType(member.GetType, GetType(System.Reflection.FieldInfo))
            End Function
 
            Private Function IsType(type As System.Type, targetType As System.Type) As Boolean
                Return type.Equals(targetType) OrElse type.IsSubclassOf(targetType)
            End Function
 
            Private Function GetMembers(type As System.Type) As List(Of System.Reflection.MemberInfo)
                Dim flags = System.Reflection.BindingFlags.Instance Or System.Reflection.BindingFlags.Public _
                    Or System.Reflection.BindingFlags.NonPublic
                Dim members = New List(Of System.Reflection.MemberInfo)
                members.AddRange(type.GetProperties(flags))
                members.AddRange(type.GetFields(flags))
                Return members
            End Function
        End Module
    End Namespace
End Namespace ' http://programmingnotes.org/

3. More Examples

Below are more examples demonstrating the use of the ‘Utils‘ Namespace. Don’t forget to include the module when running the examples!





		
		
			More Examples
			
Visual Basic .NET
			
			' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 22, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils.Objects

Module Program
    Public Class Part
        Public Property PartName As String
        Public PartId As Integer?
    End Class

    Public Structure Part2
        Public Property PartName As String
        Public PartId As Integer
    End Structure

    Sub Main(args As String())
        Try
            ' Declare source object
            Dim part1 = New Part With {
                .PartName = "crank arm",
                .PartId = 1234
            }

            ' Declare destination object
            Dim part2 = New Part2

            ' Copy matching properties and fields to destination
            part1.CopyPropsTo(part2)

            ' Display information
            Display($"{part2.PartId} - {part2.PartName}")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub

    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/
			
				
					
				
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						' ============================================================================
'    Author: Kenneth Perkins
'    Date:   Nov 22, 2020
'    Taken From: http://programmingnotes.org/
'    File: Program.vb
'    Description: The following demonstrates the use of the Utils Namespace
' ============================================================================
Option Strict On
Option Explicit On
Imports System
Imports Utils.Objects
 
Module Program
    Public Class Part
        Public Property PartName As String
        Public PartId As Integer?
    End Class
 
    Public Structure Part2
        Public Property PartName As String
        Public PartId As Integer
    End Structure
 
    Sub Main(args As String())
        Try
            ' Declare source object
            Dim part1 = New Part With {
                .PartName = "crank arm",
                .PartId = 1234
            }
 
            ' Declare destination object
            Dim part2 = New Part2
 
            ' Copy matching properties and fields to destination
            part1.CopyPropsTo(part2)
 
            ' Display information
            Display($"{part2.PartId} - {part2.PartName}")
        Catch ex As Exception
            Display(ex.ToString)
        Finally
            Console.ReadLine()
        End Try
    End Sub
 
    Public Sub Display(message As String)
        Console.WriteLine(message)
        Debug.Print(message)
    End Sub
End Module ' http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

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Posted in: Console, VB.NET Tags: object copy properties, vb.net

VB.NET || How To Copy All Properties & Fields From One Object To Another Using VB.NET

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