Reflection issue

[ECathell]

I have a routine that compares 2 intances of the same object to see if there are any changes. The problem is that even though there are no changes, it tells me there are. I have even tried running a new routine that shows a messagebox with both objects' property values. below is my code.


this is the actual comparison code:
Dim Properties() As PropertyInfo = pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
Dim PropertyItem As PropertyInfo
For Each PropertyItem In Properties
If ischanged = False Then

With PropertyItem
Dim o1 As New Object''These are just for testing and will be returned to refactored code
Dim o2 As New Object''These are just for testing and will be returned to refactored code
o1 = .GetValue(obj, Nothing)''These are just for testing and will be returned to refactored code
o2 = .GetValue(obj_o riginal, Nothing)''These are just for testing and will be returned to refactored code
'TODO Comment These Out
Debug.WriteLine (String.Format( "Property Name: {0} PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
Debug.WriteLine (String.Format( " Name {0}", .Name))
Debug.WriteLine (String.Format( " New Value {0}", o1))
Debug.WriteLine (String.Format( "Original Value {0}", o2))
'Debug.WriteLin e(String.Format (" isChanged {0}", ischanged.ToStr ing))
Debug.WriteLine (Environment.Ne wLine)
If Not o1.Equals(o2) Then

ischanged = True
End If


End With
End If
Next

This is the code that I validate with first: it displays the information properly.

Private Shared Sub validateValues( ByVal obj As Object, ByVal obj_original As Object, ByVal ptype As Type)
Dim s As New StringBuilder

Dim Properties() As PropertyInfo = ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
Dim PropertyItem As PropertyInfo
For Each PropertyItem In Properties
With PropertyItem
s.AppendFormat( "Property Name:{0} CurrentValue:{1 } OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing), ..GetValue(obj_ original, Nothing))
s.Append(Enviro nment.NewLine)

End With
Next
MessageBox.Show (s.ToString)

End Sub
--
--Eric Cathell, MCSA

[rmacias]

RE: Reflection issue

That's because the line:

If Not o1.Equals(o2) Then
ischanged = True
End If

is checking for reference equality, and not value equality. For example:

Dim myObj1 As Object = New Object()
Dim myObj2 As Object = New Object()

'Will return false because the references point to different object
MessageBox.Show (myObj1.Equals( myObj2))

myObj1 = myObj2

'Will return true because the references point to the same object
MessageBox.Show (myObj1.Equals( myObj2))

"ECathell" wrote:
[color=blue]
> I have a routine that compares 2 intances of the same object to see if there are any changes. The problem is that even though there are no changes, it tells me there are. I have even tried running a new routine that shows a messagebox with both objects' property values. below is my code.
>
>
> this is the actual comparison code:
> Dim Properties() As PropertyInfo = pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> Dim PropertyItem As PropertyInfo
> For Each PropertyItem In Properties
> If ischanged = False Then
>
> With PropertyItem
> Dim o1 As New Object''These are just for testing and will be returned to refactored code
> Dim o2 As New Object''These are just for testing and will be returned to refactored code
> o1 = .GetValue(obj, Nothing)''These are just for testing and will be returned to refactored code
> o2 = .GetValue(obj_o riginal, Nothing)''These are just for testing and will be returned to refactored code
> 'TODO Comment These Out
> Debug.WriteLine (String.Format( "Property Name: {0} PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
> Debug.WriteLine (String.Format( " Name {0}", .Name))
> Debug.WriteLine (String.Format( " New Value {0}", o1))
> Debug.WriteLine (String.Format( "Original Value {0}", o2))
> 'Debug.WriteLin e(String.Format (" isChanged {0}", ischanged.ToStr ing))
> Debug.WriteLine (Environment.Ne wLine)
> If Not o1.Equals(o2) Then
>
> ischanged = True
> End If
>
>
> End With
> End If
> Next
>
> This is the code that I validate with first: it displays the information properly.
>
> Private Shared Sub validateValues( ByVal obj As Object, ByVal obj_original As Object, ByVal ptype As Type)
> Dim s As New StringBuilder
>
> Dim Properties() As PropertyInfo = ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> Dim PropertyItem As PropertyInfo
> For Each PropertyItem In Properties
> With PropertyItem
> s.AppendFormat( "Property Name:{0} CurrentValue:{1 } OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing), ..GetValue(obj_ original, Nothing))
> s.Append(Enviro nment.NewLine)
>
> End With
> Next
> MessageBox.Show (s.ToString)
>
> End Sub
> --
> --Eric Cathell, MCSA[/color]

[rmacias]

RE: Reflection issue

That's because the line:

If Not o1.Equals(o2) Then
ischanged = True
End If

is checking for reference equality, and not value equality. For example:

Dim myObj1 As Object = New Object()
Dim myObj2 As Object = New Object()

'Will return false because the references point to different object
MessageBox.Show (myObj1.Equals( myObj2))

myObj1 = myObj2

'Will return true because the references point to the same object
MessageBox.Show (myObj1.Equals( myObj2))

"ECathell" wrote:
[color=blue]
> I have a routine that compares 2 intances of the same object to see if there are any changes. The problem is that even though there are no changes, it tells me there are. I have even tried running a new routine that shows a messagebox with both objects' property values. below is my code.
>
>
> this is the actual comparison code:
> Dim Properties() As PropertyInfo = pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> Dim PropertyItem As PropertyInfo
> For Each PropertyItem In Properties
> If ischanged = False Then
>
> With PropertyItem
> Dim o1 As New Object''These are just for testing and will be returned to refactored code
> Dim o2 As New Object''These are just for testing and will be returned to refactored code
> o1 = .GetValue(obj, Nothing)''These are just for testing and will be returned to refactored code
> o2 = .GetValue(obj_o riginal, Nothing)''These are just for testing and will be returned to refactored code
> 'TODO Comment These Out
> Debug.WriteLine (String.Format( "Property Name: {0} PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
> Debug.WriteLine (String.Format( " Name {0}", .Name))
> Debug.WriteLine (String.Format( " New Value {0}", o1))
> Debug.WriteLine (String.Format( "Original Value {0}", o2))
> 'Debug.WriteLin e(String.Format (" isChanged {0}", ischanged.ToStr ing))
> Debug.WriteLine (Environment.Ne wLine)
> If Not o1.Equals(o2) Then
>
> ischanged = True
> End If
>
>
> End With
> End If
> Next
>
> This is the code that I validate with first: it displays the information properly.
>
> Private Shared Sub validateValues( ByVal obj As Object, ByVal obj_original As Object, ByVal ptype As Type)
> Dim s As New StringBuilder
>
> Dim Properties() As PropertyInfo = ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> Dim PropertyItem As PropertyInfo
> For Each PropertyItem In Properties
> With PropertyItem
> s.AppendFormat( "Property Name:{0} CurrentValue:{1 } OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing), ..GetValue(obj_ original, Nothing))
> s.Append(Enviro nment.NewLine)
>
> End With
> Next
> MessageBox.Show (s.ToString)
>
> End Sub
> --
> --Eric Cathell, MCSA[/color]

[ECathell]

Re: Reflection issue

So then how do i check for value equality?

--
--Eric Cathell, MCSA
"rmacias" <rmacias@newsgr oup.nospam> wrote in message
news:D16B1F16-8E33-4F04-95FD-BA2FD27CA76B@mi crosoft.com...[color=blue]
> That's because the line:
>
> If Not o1.Equals(o2) Then
> ischanged = True
> End If
>
> is checking for reference equality, and not value equality. For example:
>
> Dim myObj1 As Object = New Object()
> Dim myObj2 As Object = New Object()
>
> 'Will return false because the references point to different object
> MessageBox.Show (myObj1.Equals( myObj2))
>
> myObj1 = myObj2
>
> 'Will return true because the references point to the same object
> MessageBox.Show (myObj1.Equals( myObj2))
>
> "ECathell" wrote:
>[color=green]
>> I have a routine that compares 2 intances of the same object to see if
>> there are any changes. The problem is that even though there are no
>> changes, it tells me there are. I have even tried running a new routine
>> that shows a messagebox with both objects' property values. below is my
>> code.
>>
>>
>> this is the actual comparison code:
>> Dim Properties() As PropertyInfo =
>> pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> Dim PropertyItem As PropertyInfo
>> For Each PropertyItem In Properties
>> If ischanged = False Then
>>
>> With PropertyItem
>> Dim o1 As New Object''These are just for testing and will be
>> returned to refactored code
>> Dim o2 As New Object''These are just for testing and will be
>> returned to refactored code
>> o1 = .GetValue(obj, Nothing)''These are just for testing and
>> will be returned to refactored code
>> o2 = .GetValue(obj_o riginal, Nothing)''These are just for
>> testing and will be returned to refactored code
>> 'TODO Comment These Out
>> Debug.WriteLine (String.Format( "Property Name: {0}
>> PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
>> Debug.WriteLine (String.Format( " Name {0}", .Name))
>> Debug.WriteLine (String.Format( " New Value {0}", o1))
>> Debug.WriteLine (String.Format( "Original Value {0}", o2))
>> 'Debug.WriteLin e(String.Format (" isChanged {0}",
>> ischanged.ToStr ing))
>> Debug.WriteLine (Environment.Ne wLine)
>> If Not o1.Equals(o2) Then
>>
>> ischanged = True
>> End If
>>
>>
>> End With
>> End If
>> Next
>>
>> This is the code that I validate with first: it displays the information
>> properly.
>>
>> Private Shared Sub validateValues( ByVal obj As Object, ByVal obj_original
>> As Object, ByVal ptype As Type)
>> Dim s As New StringBuilder
>>
>> Dim Properties() As PropertyInfo =
>> ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> Dim PropertyItem As PropertyInfo
>> For Each PropertyItem In Properties
>> With PropertyItem
>> s.AppendFormat( "Property Name:{0} CurrentValue:{1 }
>> OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing),
>> ..GetValue(obj_ original, Nothing))
>> s.Append(Enviro nment.NewLine)
>>
>> End With
>> Next
>> MessageBox.Show (s.ToString)
>>
>> End Sub
>> --
>> --Eric Cathell, MCSA[/color][/color]

[rmacias]

Re: Reflection issue

Honestly, that depends on what the underlying type actually is. The Equals()
method in System.Object checks for reference equality. However, in a lot of
reference types derived from System.Object, the actual type overrides the
Equals() method to check for value equality (like System.String).

What are the System.Type values are you expecting on these properties? You
can try casting them to those specified types and then checking the values
using that types Equals() method (assuming it checks for value equality).

"ECathell" wrote:
[color=blue]
> So then how do i check for value equality?
>
> --
> --Eric Cathell, MCSA
> "rmacias" <rmacias@newsgr oup.nospam> wrote in message
> news:D16B1F16-8E33-4F04-95FD-BA2FD27CA76B@mi crosoft.com...[color=green]
> > That's because the line:
> >
> > If Not o1.Equals(o2) Then
> > ischanged = True
> > End If
> >
> > is checking for reference equality, and not value equality. For example:
> >
> > Dim myObj1 As Object = New Object()
> > Dim myObj2 As Object = New Object()
> >
> > 'Will return false because the references point to different object
> > MessageBox.Show (myObj1.Equals( myObj2))
> >
> > myObj1 = myObj2
> >
> > 'Will return true because the references point to the same object
> > MessageBox.Show (myObj1.Equals( myObj2))
> >
> > "ECathell" wrote:
> >[color=darkred]
> >> I have a routine that compares 2 intances of the same object to see if
> >> there are any changes. The problem is that even though there are no
> >> changes, it tells me there are. I have even tried running a new routine
> >> that shows a messagebox with both objects' property values. below is my
> >> code.
> >>
> >>
> >> this is the actual comparison code:
> >> Dim Properties() As PropertyInfo =
> >> pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> >> Dim PropertyItem As PropertyInfo
> >> For Each PropertyItem In Properties
> >> If ischanged = False Then
> >>
> >> With PropertyItem
> >> Dim o1 As New Object''These are just for testing and will be
> >> returned to refactored code
> >> Dim o2 As New Object''These are just for testing and will be
> >> returned to refactored code
> >> o1 = .GetValue(obj, Nothing)''These are just for testing and
> >> will be returned to refactored code
> >> o2 = .GetValue(obj_o riginal, Nothing)''These are just for
> >> testing and will be returned to refactored code
> >> 'TODO Comment These Out
> >> Debug.WriteLine (String.Format( "Property Name: {0}
> >> PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
> >> Debug.WriteLine (String.Format( " Name {0}", .Name))
> >> Debug.WriteLine (String.Format( " New Value {0}", o1))
> >> Debug.WriteLine (String.Format( "Original Value {0}", o2))
> >> 'Debug.WriteLin e(String.Format (" isChanged {0}",
> >> ischanged.ToStr ing))
> >> Debug.WriteLine (Environment.Ne wLine)
> >> If Not o1.Equals(o2) Then
> >>
> >> ischanged = True
> >> End If
> >>
> >>
> >> End With
> >> End If
> >> Next
> >>
> >> This is the code that I validate with first: it displays the information
> >> properly.
> >>
> >> Private Shared Sub validateValues( ByVal obj As Object, ByVal obj_original
> >> As Object, ByVal ptype As Type)
> >> Dim s As New StringBuilder
> >>
> >> Dim Properties() As PropertyInfo =
> >> ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
> >> Dim PropertyItem As PropertyInfo
> >> For Each PropertyItem In Properties
> >> With PropertyItem
> >> s.AppendFormat( "Property Name:{0} CurrentValue:{1 }
> >> OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing),
> >> ..GetValue(obj_ original, Nothing))
> >> s.Append(Enviro nment.NewLine)
> >>
> >> End With
> >> Next
> >> MessageBox.Show (s.ToString)
> >>
> >> End Sub
> >> --
> >> --Eric Cathell, MCSA[/color][/color]
>
>
>[/color]

[ECathell]

Re: Reflection issue

I am using reflection to view the property values of a custom class. The
strange thing is on my non-complex objects this already works fine. It is
just on this class for now.All my classes have an abstract base and a
concrete class. However, this class has enumerations attached. Maybe that is
where my error is because my other classes dont do this...


Region "PrePack Enumeration"
Public Enum PrePackTypes
ICEPACK
TRAYPACK
End Enum
' Private mPrepack As Boolean
Private xPrepack As PrePackTypes
Public Shadows Property Prepack() As PrePackTypes
Get
Select Case MyBase.PrePack
Case True
xPrepack = PrePackTypes.TR AYPACK
Case False
xPrepack = PrePackTypes.IC EPACK

End Select

Return xPrepack
End Get
Set(ByVal Value As PrePackTypes)

xPrepack = Value
Select Case xPrepack
Case PrePackTypes.IC EPACK
MyBase.PrePack = False
Case PrePackTypes.TR AYPACK
MyBase.PrePack = True
End Select
End Set
End Property
#End Region

#Region "TareType Enumeration"
Public Enum TareTypes
STANDARD
PERCENTAGE
End Enum

'Private mTareType As Boolean
Private xTaretype As TareTypes
Public Shadows Property TareType() As TareTypes
Get
Select Case MyBase.TareType
Case True
xTaretype = TareTypes.PERCE NTAGE
Case False
xTaretype = TareTypes.STAND ARD
End Select
Return xTaretype

End Get
Set(ByVal Value As TareTypes)
xTaretype = Value
Select Case xTaretype
Case TareTypes.PERCE NTAGE
MyBase.TareType = True
Case TareTypes.STAND ARD
MyBase.TareType = False
End Select
End Set
End Property
'
#End Region

#Region "StorageTyp es Enumeration"
Public Enum StorageTypes
REFRIGERATED
FROZEN
End Enum
'Private mStorage As String
Private xStorage As StorageTypes
Public Shadows Property Storage() As StorageTypes

Get
Select Case mStorage
Case "REFRIGERAT ED"
xStorage = StorageTypes.RE FRIGERATED
Case "FROZEN"
xStorage = StorageTypes.FR OZEN
End Select

Return xStorage

End Get
Set(ByVal Value As StorageTypes)
xStorage = Value
Select Case xStorage
Case StorageTypes.FR OZEN
mStorage = "FROZEN"
Case StorageTypes.RE FRIGERATED
mStorage = "REFRIGERAT ED"
End Select

End Set
End Property
#End Region

#Region "DateTypes Enumeration"
Public Enum DateTypes
[CODE]
[PACKED]
[SELL_BY]
[JULIAN]
End Enum

'Private mDateType As String
Private xDateType As DateTypes
Public Shadows Property DateType() As DateTypes
Get
Select Case mDateType
Case "CODE"
xDateType = DateTypes.CODE
Case "SELL-BY"
xDateType = DateTypes.SELL_ BY
Case "PACKED"
xDateType = DateTypes.PACKE D
Case "JULIAN"
xDateType = DateTypes.JULIA N

End Select
Return xDateType

End Get
Set(ByVal Value As DateTypes)
xDateType = Value
Select Case xDateType
Case DateTypes.CODE
mDateType = "CODE"
Case DateTypes.PACKE D
mDateType = "PACKED"
Case DateTypes.SELL_ BY
mDateType = "SELL-BY"
Case DateTypes.JULIA N
mdatetype = "JULIAN"
End Select

End Set
End Property


#End Region

#Region "WeightType s Enumeration"
Public Enum WeightTypes
[FIXED]
[CATCH]
[KEYED]
End Enum
'Private mWeightType As String
Private xWeightType As WeightTypes
Public Shadows Property WeightType() As WeightTypes
Get

Select Case mWeightType
Case "FIXED"
xWeightType = WeightTypes.FIX ED

Case "CATCH"
xWeightType = WeightTypes.CAT CH

Case "KEYED"
xWeightType = WeightTypes.KEY ED

End Select

Return xWeightType

End Get
Set(ByVal Value As WeightTypes)
xWeightType = Value
Select Case xWeightType
Case WeightTypes.CAT CH
mWeightType = "CATCH"
Case WeightTypes.FIX ED
mWeightType = "FIXED"
Case WeightTypes.KEY ED
mWeightType = "KEYED"
End Select

End Set
End Property
'
#End Region

--
--Eric Cathell, MCSA
"rmacias" <rmacias@newsgr oup.nospam> wrote in message
news:BBED5CBD-3EE6-41F0-B1E6-635208956F3C@mi crosoft.com...[color=blue]
> Honestly, that depends on what the underlying type actually is. The
> Equals()
> method in System.Object checks for reference equality. However, in a lot
> of
> reference types derived from System.Object, the actual type overrides the
> Equals() method to check for value equality (like System.String).
>
> What are the System.Type values are you expecting on these properties?
> You
> can try casting them to those specified types and then checking the values
> using that types Equals() method (assuming it checks for value equality).
>
> "ECathell" wrote:
>[color=green]
>> So then how do i check for value equality?
>>
>> --
>> --Eric Cathell, MCSA
>> "rmacias" <rmacias@newsgr oup.nospam> wrote in message
>> news:D16B1F16-8E33-4F04-95FD-BA2FD27CA76B@mi crosoft.com...[color=darkred]
>> > That's because the line:
>> >
>> > If Not o1.Equals(o2) Then
>> > ischanged = True
>> > End If
>> >
>> > is checking for reference equality, and not value equality. For
>> > example:
>> >
>> > Dim myObj1 As Object = New Object()
>> > Dim myObj2 As Object = New Object()
>> >
>> > 'Will return false because the references point to different object
>> > MessageBox.Show (myObj1.Equals( myObj2))
>> >
>> > myObj1 = myObj2
>> >
>> > 'Will return true because the references point to the same object
>> > MessageBox.Show (myObj1.Equals( myObj2))
>> >
>> > "ECathell" wrote:
>> >
>> >> I have a routine that compares 2 intances of the same object to see if
>> >> there are any changes. The problem is that even though there are no
>> >> changes, it tells me there are. I have even tried running a new
>> >> routine
>> >> that shows a messagebox with both objects' property values. below is
>> >> my
>> >> code.
>> >>
>> >>
>> >> this is the actual comparison code:
>> >> Dim Properties() As PropertyInfo =
>> >> pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> >> Dim PropertyItem As PropertyInfo
>> >> For Each PropertyItem In Properties
>> >> If ischanged = False Then
>> >>
>> >> With PropertyItem
>> >> Dim o1 As New Object''These are just for testing and will
>> >> be
>> >> returned to refactored code
>> >> Dim o2 As New Object''These are just for testing and will
>> >> be
>> >> returned to refactored code
>> >> o1 = .GetValue(obj, Nothing)''These are just for testing
>> >> and
>> >> will be returned to refactored code
>> >> o2 = .GetValue(obj_o riginal, Nothing)''These are just for
>> >> testing and will be returned to refactored code
>> >> 'TODO Comment These Out
>> >> Debug.WriteLine (String.Format( "Property Name: {0}
>> >> PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
>> >> Debug.WriteLine (String.Format( " Name {0}",
>> >> .Name))
>> >> Debug.WriteLine (String.Format( " New Value {0}", o1))
>> >> Debug.WriteLine (String.Format( "Original Value {0}", o2))
>> >> 'Debug.WriteLin e(String.Format (" isChanged {0}",
>> >> ischanged.ToStr ing))
>> >> Debug.WriteLine (Environment.Ne wLine)
>> >> If Not o1.Equals(o2) Then
>> >>
>> >> ischanged = True
>> >> End If
>> >>
>> >>
>> >> End With
>> >> End If
>> >> Next
>> >>
>> >> This is the code that I validate with first: it displays the
>> >> information
>> >> properly.
>> >>
>> >> Private Shared Sub validateValues( ByVal obj As Object, ByVal
>> >> obj_original
>> >> As Object, ByVal ptype As Type)
>> >> Dim s As New StringBuilder
>> >>
>> >> Dim Properties() As PropertyInfo =
>> >> ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> >> Dim PropertyItem As PropertyInfo
>> >> For Each PropertyItem In Properties
>> >> With PropertyItem
>> >> s.AppendFormat( "Property Name:{0} CurrentValue:{1 }
>> >> OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing),
>> >> ..GetValue(obj_ original, Nothing))
>> >> s.Append(Enviro nment.NewLine)
>> >>
>> >> End With
>> >> Next
>> >> MessageBox.Show (s.ToString)
>> >>
>> >> End Sub
>> >> --
>> >> --Eric Cathell, MCSA[/color]
>>
>>
>>[/color][/color]

[ECathell]

Re: Reflection issue

I fixed it...I think it had an issue with my shadows properties...ch anged
their name and voila....

Thanks for the help....


--
--Eric Cathell, MCSA
"rmacias" <rmacias@newsgr oup.nospam> wrote in message
news:BBED5CBD-3EE6-41F0-B1E6-635208956F3C@mi crosoft.com...[color=blue]
> Honestly, that depends on what the underlying type actually is. The
> Equals()
> method in System.Object checks for reference equality. However, in a lot
> of
> reference types derived from System.Object, the actual type overrides the
> Equals() method to check for value equality (like System.String).
>
> What are the System.Type values are you expecting on these properties?
> You
> can try casting them to those specified types and then checking the values
> using that types Equals() method (assuming it checks for value equality).
>
> "ECathell" wrote:
>[color=green]
>> So then how do i check for value equality?
>>
>> --
>> --Eric Cathell, MCSA
>> "rmacias" <rmacias@newsgr oup.nospam> wrote in message
>> news:D16B1F16-8E33-4F04-95FD-BA2FD27CA76B@mi crosoft.com...[color=darkred]
>> > That's because the line:
>> >
>> > If Not o1.Equals(o2) Then
>> > ischanged = True
>> > End If
>> >
>> > is checking for reference equality, and not value equality. For
>> > example:
>> >
>> > Dim myObj1 As Object = New Object()
>> > Dim myObj2 As Object = New Object()
>> >
>> > 'Will return false because the references point to different object
>> > MessageBox.Show (myObj1.Equals( myObj2))
>> >
>> > myObj1 = myObj2
>> >
>> > 'Will return true because the references point to the same object
>> > MessageBox.Show (myObj1.Equals( myObj2))
>> >
>> > "ECathell" wrote:
>> >
>> >> I have a routine that compares 2 intances of the same object to see if
>> >> there are any changes. The problem is that even though there are no
>> >> changes, it tells me there are. I have even tried running a new
>> >> routine
>> >> that shows a messagebox with both objects' property values. below is
>> >> my
>> >> code.
>> >>
>> >>
>> >> this is the actual comparison code:
>> >> Dim Properties() As PropertyInfo =
>> >> pType.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> >> Dim PropertyItem As PropertyInfo
>> >> For Each PropertyItem In Properties
>> >> If ischanged = False Then
>> >>
>> >> With PropertyItem
>> >> Dim o1 As New Object''These are just for testing and will
>> >> be
>> >> returned to refactored code
>> >> Dim o2 As New Object''These are just for testing and will
>> >> be
>> >> returned to refactored code
>> >> o1 = .GetValue(obj, Nothing)''These are just for testing
>> >> and
>> >> will be returned to refactored code
>> >> o2 = .GetValue(obj_o riginal, Nothing)''These are just for
>> >> testing and will be returned to refactored code
>> >> 'TODO Comment These Out
>> >> Debug.WriteLine (String.Format( "Property Name: {0}
>> >> PropertyType:{1 }", PropertyItem.Na me, PropertyItem.Pr opertyType))
>> >> Debug.WriteLine (String.Format( " Name {0}",
>> >> .Name))
>> >> Debug.WriteLine (String.Format( " New Value {0}", o1))
>> >> Debug.WriteLine (String.Format( "Original Value {0}", o2))
>> >> 'Debug.WriteLin e(String.Format (" isChanged {0}",
>> >> ischanged.ToStr ing))
>> >> Debug.WriteLine (Environment.Ne wLine)
>> >> If Not o1.Equals(o2) Then
>> >>
>> >> ischanged = True
>> >> End If
>> >>
>> >>
>> >> End With
>> >> End If
>> >> Next
>> >>
>> >> This is the code that I validate with first: it displays the
>> >> information
>> >> properly.
>> >>
>> >> Private Shared Sub validateValues( ByVal obj As Object, ByVal
>> >> obj_original
>> >> As Object, ByVal ptype As Type)
>> >> Dim s As New StringBuilder
>> >>
>> >> Dim Properties() As PropertyInfo =
>> >> ptype.GetProper ties(BindingFla gs.Public Or BindingFlags.In stance)
>> >> Dim PropertyItem As PropertyInfo
>> >> For Each PropertyItem In Properties
>> >> With PropertyItem
>> >> s.AppendFormat( "Property Name:{0} CurrentValue:{1 }
>> >> OriginalValue:{ 1}", .Name, .GetValue(obj, Nothing),
>> >> ..GetValue(obj_ original, Nothing))
>> >> s.Append(Enviro nment.NewLine)
>> >>
>> >> End With
>> >> Next
>> >> MessageBox.Show (s.ToString)
>> >>
>> >> End Sub
>> >> --
>> >> --Eric Cathell, MCSA[/color]
>>
>>
>>[/color][/color]