Serializing a dataset inherited from a typed dataset

28 Dec 2006 4:44 PM

Kevin

In .Net 2.0 I have a dataset that inherits from a typed dataset
(created using the built in tools).

The typed dataset is serializable, and when I look at the source in the
generated vb class it has lots of stuff to do with serializing in it.
When I try to serialize it, it all works fine.

I would think that if I inherit from this typed dataset then it would
also inherit all the serializable stuff but it doesnt seem to. When I
try I get an error saying:

Type 'HHD_.MeterTree.ConsViewerDataset' in Assembly 'HHD_.MeterTree,
Version=1.0.0.1, Culture=neutral, PublicKeyToken=0b07967f4983a577' is
not marked as serializable.

i have read around and but most answers dont seem to relate inheriting
from a typed dataset and involve writing lots of code to implement
serializable, however this seems unnecessary as my base class has
everything I need surely!

I have added:
'<Serializable()> _

and

    Public Overrides Sub GetObjectData(ByVal info As
System.Runtime.Serialization.SerializationInfo, ByVal context As
System.Runtime.Serialization.StreamingContext)
        MyBase.GetSerializationData(info, context)
    End Sub
to my inherited class
however now it goes into 'GetObjectData' but then comes up with the
error:
Member 'XmlDiffGram' was not found.

please, someone help me!!!

Thanks in advance.
Kevin

28 Dec 2006 5:00 PM

Dave Sexton

Hi Kevin,

You need the SerializableAttribute just like you stated, however, you don't
have to override GetObjectData. That method is for the ISerializable
interface, implemented by DataSet. Anyway, in your implementation you're
calling the wrong method on MyBase. It shouldn't be GetSerializationData,
it should be MyBase.GetObjectData, but you don't need the override anyway
unless your class needs to actually participate in the serialization
process.

--
Dave Sexton
http://davesexton.com/blog

Show quote

"Kevin" <kevinherr***@lycos.co.uk> wrote in message
news:1167324271.418182.153860@s34g2000cwa.googlegroups.com...
> In .Net 2.0 I have a dataset that inherits from a typed dataset
> (created using the built in tools).
>
> The typed dataset is serializable, and when I look at the source in the
> generated vb class it has lots of stuff to do with serializing in it.
> When I try to serialize it, it all works fine.
>
> I would think that if I inherit from this typed dataset then it would
> also inherit all the serializable stuff but it doesnt seem to. When I
> try I get an error saying:
>
> Type 'HHD_.MeterTree.ConsViewerDataset' in Assembly 'HHD_.MeterTree,
> Version=1.0.0.1, Culture=neutral, PublicKeyToken=0b07967f4983a577' is
> not marked as serializable.
>
> i have read around and but most answers dont seem to relate inheriting
> from a typed dataset and involve writing lots of code to implement
> serializable, however this seems unnecessary as my base class has
> everything I need surely!
>
> I have added:
> '<Serializable()> _
>
> and
>
>    Public Overrides Sub GetObjectData(ByVal info As
> System.Runtime.Serialization.SerializationInfo, ByVal context As
> System.Runtime.Serialization.StreamingContext)
>        MyBase.GetSerializationData(info, context)
>    End Sub
> to my inherited class
> however now it goes into 'GetObjectData' but then comes up with the
> error:
> Member 'XmlDiffGram' was not found.
>
> please, someone help me!!!
>
> Thanks in advance.
> Kevin
>

2 Jan 2007 10:02 AM

Kevin

Thanks for your reply Dave. Not sure why I didn't make the correct
mybase call, but i read somewhere that that was the call i needed to
make.

Anyway that fixes it a little, but now I get a
The constructor to deserialize an object
of type [myDataSetExt] was not found.

Some further digging reveals that this is a known issue with inheriting
from strongly typed datasets:

http://groups.google.co.uk/group/microsoft.public.dotnet.framework.adonet/browse_thread/thread/43103a7439cad95

I am trying to modify a visualizer for datasets btw.
http://www.codeproject.com/dotnet/DataSet_Watch2.asp

Thanks for your help.
Kevin