Persistence

[Mark]

Hello, 

I have the need to be able to persist and restore the state of a RadDataFilter.  I was hoping to be able to save-off and restore the FilterDescriptors collection, but unfortunately it is read-only.  So, what would be the best approach to making this happen?  Is persistence supported at all?

Thanks,
Mark

[Rossen Hristov]

Hi Mark,

Every collection property out there (the entire .NET Framework for example) should be read-only.

Usually, when you want to add something to a collection you add it to the collection instead of assigning a whole new reference pointing to a collection object.

Anyway, I am sure that this Code Library will get you started. What it does is save and restore FilterDescriptors by using XML.

Best wishes,
Ross
the Telerik team

[Mark]

Hi Ross,

Thanks for your reply.  I would generally agree with your comments about collections, however, the persistence infrastructure I am trying to use expects to save off the entire collection and not simply its contents.  I can imagine a couple of workarounds, but wanted to find out what other approaches might be out there.  This library looks promising and I will look into it right away.  (FYI, the link you left was not working for me, but I found the library nonetheless.)

Thanks for your help!
Mark.

[Rossen Hristov]

Hello Mark,

I simply cannot create a setter for a collection property. I will break all design principles that I am trying to follow. I am sure that this can be worked around in many different ways instead of adding a setter.

The idea of the article is simple -- each FilterDescriptor object has 4 meaningful properties. Simply read them, store them in some kind of medium of your choice and then do the opposite by reading them, re-creating the FilterDescriptor and adding it to the collection. This RadGridView example does something similar with the grid's FilterDescriptors which are the same as RadDataFilter's. It should be the same.

I hope this helps.

Regards,
Ross
the Telerik team

[Mark]

Hi Ross,

I completely agree with your lack of desire to add a setter - I did not mean in any way to suggest that you should.  In fact, this issue has identified a flaw in our persistence infrastructure.  As it turns out the filter system that I am replacing with the RadDataFilter relied on setting a collection property - which is definitely not the best approach.

I am sure that I will be able to work around it, and the extension library you pointed me to will be a helpful resource.  If I cannot, then we will make changes to our persistence layer.  I am just glad to hear that we should be able to re-populate the collection with persisted FilterDescriptors - that should be all I really need.

Thanks again for your support,
Mark.