compare value equality of objects - vb.net

Question

I would like to know the best way to compare 2 complex objects to know if they are equal by value, ie, their properties are the same? I tried the serialize method and not sure why they are not equal by value
Dim stream As New MemoryStream()
Dim bstream As New MemoryStream()
Dim clientOne As Jewellery.ClientInfo = New Jewellery.ClientInfo(New Jewellery.Company("a", "", "", "b", "", "e"), New Jewellery.Customer("a", "b", "c", "d", "", "", "", "f"))
Dim clientTwo As Jewellery.ClientInfo = New Jewellery.ClientInfo(New Jewellery.Company("a", "", "", "b", "", "e"), New Jewellery.Customer("a", "b", "c", "d", "", "", "", "f"))
formatter.Serialize(stream, clientOne)
formatter.Serialize(bstream, clientTwo)
Dim streamOneBytes As Byte() = stream.ToArray()
Dim streamTwoBytes As Byte() = bstream.ToArray()
Dim streamToCompareBytes As Byte() = streamToCompare.ToArray()
Dim i As Int16 = 0
Dim flag As Boolean
If streamOneBytes.Length <> streamTwoBytes.Length Then
MsgBox("False")
flag = False
Else
While i < streamOneBytes.Count
If streamOneBytes(i) <> streamTwoBytes(i) Then
flag = "False"
Else : flag = "True"
End If
i = i + 1
End While
End If
As you see in the above code, when I initialize 2 objects of the same type and compare, it works correctly. But when I add one object to say a List and then retrieve and compare to an object of similar type, it fails saying the binary width are different for both. Any advice? Thanks

Answer 1

public class IntegerPropertyEqualityCompare : IEqualityComparer<Main>
{
#region IEqualityComparer<Main> Members
public bool Equals( Main x, Main y )
{
return x.IntegerProperty == y.IntegerProperty;
}
public int GetHashCode( Main obj )
{
return obj.IntegerProperty.GetHashCode() ^ obj.StringProperty.GetHashCode();
}
#endregion
}
public class StringPropertyEqualityCompare : IEqualityComparer<Main>
{
#region IEqualityComparer<Main> Members
public bool Equals( Main x, Main y )
{
return x.StringProperty == y.StringProperty;
}
public int GetHashCode( Main obj )
{
return obj.IntegerProperty.GetHashCode() ^ obj.StringProperty.GetHashCode();
}
#endregion
}
public class AllPropertiesEqualityCompare : IEqualityComparer<Main>
{
#region IEqualityComparer<Main> Members
public bool Equals( Main x, Main y )
{
return ( x.IntegerProperty == y.IntegerProperty ) && ( x.StringProperty == y.StringProperty );
}
public int GetHashCode( Main obj )
{
return obj.IntegerProperty.GetHashCode() ^ obj.StringProperty.GetHashCode();
}
#endregion
}
public abstract class Main
{
public int IntegerProperty { get; set; }
public string StringProperty { get; set; }
public bool Equals( IEqualityComparer<Main> comparer, Main other )
{
return comparer.Equals( this, other );
}
}
public class ConcreteA : Main
{ }
public class ConcreteB : Main
{ }
class TemporaryTest
{
public static void Run()
{
var a = new ConcreteA();
a.IntegerProperty = 1;
a.StringProperty = "some";
var b = new ConcreteB();
b.IntegerProperty = 1;
a.StringProperty = "other";
Console.WriteLine( a.Equals( new IntegerPropertyEqualityCompare(), b ) );
Console.WriteLine( a.Equals( new StringPropertyEqualityCompare(), b ) );
Console.WriteLine( a.Equals( new AllPropertiesEqualityCompare(), b ) );
}
}
Maybe then somthing like this?

Answer 2

I'm not sure that I understand what you want to do.
So I go with IComparable<T>.