How to Use Reflection to Compare Two Objects

The Code

Private Function IsEqualTo(ByVal objA As Object, ByVal objB As Object) As Boolean

   Dim different As Boolean    = False
   Dim type1 As Type           = objA.GetType
   Dim props() As PropertyInfo = type1.GetProperties

   For Each p As PropertyInfo In props
         Dim pValue As Object = p.GetValue(objA, Nothing)
         Dim pValue2 As Object = p.GetValue(objB, Nothing)
       
         If pValue <> pValue2 Then
            different = True
            Exit For
         End If
      Next

   Return Not different

End Function

This code snippet is pretty simple. It uses reflection to iterate over the properties of one Object (objA) and compares each property to the other object (objB) of the same type.

How would you use it?

This example will return "equal"

Dim objA as New Person
Dim objB as New Person

objA.FirstName = 'John'
objA.LastName = 'Smith'
objA.Phone = '555-1234'

objB.FirstName = 'John'
objB.LastName = 'Smith'
objB.Phone = '555-1234'

If IsEqualTo(objA,objB) Then
   MsgBox("equal")
Else
   MsgBox("not equal")
End If

This example will return "not equal"

Dim objA as New Person
Dim objB as New Person

objA.FirstName = 'John'
objA.LastName = 'Smith'
objA.Phone = '555-1234'

objB.FirstName = 'John'
objB.LastName = 'Smith'
objB.Phone = '555-1235'

If IsEqualTo(objA,objB) Then
   MsgBox("equal")
Else
   MsgBox("not equal")
End If