good / evil [good wins :) - Resolved]

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...

VB Code:

<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.

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...:bigyello:

Edit: BTW, I'm not so clever that I could have thought of this myself :p , 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.

Hello Again.

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

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.

Would you mind casting your eye over this...

VB Code:

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?

Hi.

That exactly how I would do it.

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

VB Code:

<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.

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.

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.

Cool. My programs is a bit more streamlined now.

Cheers for the help. :thumb::afrog: