good / evil [good wins :) - Resolved]

[wossname]

Is it possible or even good or bad practice to code a class so that it can serialize itself?

I have a class that currently only serializes one of its data members (an array). But how about this...

<Serializable()> Public Class X
    Shared Function LoadNewObject(ByVal path As String) As X
 
        Dim binser As BinaryFormatter = New BinaryFormatter
        Dim input As Stream = New FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None)
 
        Dim temp As X
        temp = binser.Deserialize(input)
        input.close()
 
        Return temp
 
    End Function
 
    Public Sub SaveSelf(ByVal path As String)
 
        Dim binser As BinaryFormatter = New BinaryFormatter
        Dim output As Stream = New FileStream(Path, FileMode.Create, FileAccess.Write, FileShare.None)
 
        binser.Serialize(output, Me)
 
        output.Close()
 
    End Sub
End Class

Your thoughts please.

[pax]

Hi.

I don't see anything wrong with it. In fact, I don't even see any other way of doing it.
I do that all the time, when making configuration files and it works like a charm.

BUT, I'm self-thought, so I have no idea what a pro migth have to say, so my humble opinion might not be worth the time it took to write this...

Edit: BTW, I'm not so clever that I could have thought of this myself , so I'm pretty sure I once saw a sample on MSDN on how to do it. So if my memory serves, MS encourages this way of doing it.

[pax]

Hello Again.

I just found this link, so it appears my memory aren't a complete wasteland (yippie )

http://msdn.microsoft.com/library/de...appsettnet.asp

This is a few samples from MSDN where MS shows different ways of doing it.
Scroll down a little, and you should see a header called "Creating a Custom Application Configuration Class".
That's a sample where they serialize the entire class so I guess it's ok to do it.

[wossname]

Would you mind casting your eye over this...

Shared Function FromFile(ByVal path As String) As BoundaryDataStorage
 
        If File.Exists(path) Then
 
            'deserializes the array of boundaries from a binary file
            Dim binser As BinaryFormatter
            Dim input As Stream
            Dim temp As BoundaryDataStorage
 
            Try
                'load the file
                binser = New BinaryFormatter                
                input = New FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None)             
                temp = binser.Deserialize(input)    [b]'<<<<<<<<<<<<<<<<<<<[/b]
                input.Close()
 
                temp.Path = path
                Return temp
            Catch ex As Exception
                If Not IsNothing(input) Then input.Close()
                temp = Nothing
                Return Nothing
            End Try
 
        End If
 
    End Function
 
    Public Function SaveBoundaryDataBinary(ByVal path As String) As Boolean
        Dim binser As BinaryFormatter
        Dim output As Stream
 
        itsPath = path.Trim
 
        Try
            binser = New BinaryFormatter
            output = New FileStream(itsPath, FileMode.Create, FileAccess.Write, FileShare.None)
 
            Dirty = False           'set flag BEFORE saving because the flag is saved too!
            binser.Serialize(output, Me)    [b]'<<<<<<<<<<<<<<<<<<<[/b]
 
            output.Close()
 
            Return True          'success!
        Catch ex As Exception
            If Not IsNothing(output) Then output.Close()
            Return False
        End Try
 
    End Function

Does this seem like a reasonable approach?

[pax]

Hi.

That exactly how I would do it.

You could set the "NonSerialized" attribute for the "Dirty" variable to prevent it from being serialized.

<NonSerialized()> Private Dirty As Boolean

That way, you can have lot's of internal variables, and only have it serialize the ones that are neccesary.

[wossname]

OK...I have declared the flag thus:

<NonSerialized()>Private itsDirty As Boolean = False

when I have run FromFile(...) and I have my new object, will itsDirty contain false because I have set it as the default value?

I realise I can't use the constructor to set it when deserializing.

[pax]

Hi.

Yes. All variables and properties that are not included in the file (either because they are not serialized or because they have been added after the creation of a file) will use their defaultvalue.

[wossname]

Cool. My programs is a bit more streamlined now.

Cheers for the help.