Dynamic Fields

[Guru]

Is it possible to take objectmodel and pass each objects "ID" property to an expressioneditor as a field? or maybe each column id in a datatable?

[Guru]

If I create a datatable and pass its first row to the expression editor it works, but the editor seems disabled... it shows the fields and shows their datatypes when selected but you cant enter or add text to the expressiontext field...

[Dimitrina]

Hello,

 Have you tried working with the DefaultView of the DataTable and pass the first item of the DefaultView instead?

All the best,
Didie
the Telerik team

[Guru]

That gives me the same result, it seems to fully functioning as in you can click on ay constant or field and it shows info but you cannot get anything into the expressiontexxt field.

[Dimitrina]

Hello,

We have checked the case in details and unfortunately you are right. Such a scenario is not supported. 

Regards,
Didie
the Telerik team

[Guru]

Ok so what is supported?
Documentation on this component is seriously lacking, it only shows it hooked up to a grid that uses an object model datasource... Doesn't really show any other uses...
I would like to see a end user guide too such as the datfilter has which was helpful.

Is it possible to pass this component anything other than a hard coded object model?
If so, please give an example... I have seen a few people out there attempting this and no solid answers to their problem.

[Dimitrina]

Hello,

 What is supported are Objects with Properties. If you have set the Item for the ExpressionEditor to be an Object, you should have the field you would like to access defined as a Property in the class of the Object.

Kind regards,
Didie
the Telerik team

[Guru]

Can you say what kind of objects? any other than hard coded models?
I am dealing with unknown fields until runtime... can I use dynamic/expandos?

[Stefan Dobrev]

Hi Zack,

Let me jump into this forum thread. My name is Stefan Dobrev and I'm the author of the RadExpressionEditor component and the expression engine behind it. You are absolutely right that the component lacks documentation and more user case scenario examples. We are sorry for this and will try to improve this one step at at time for the future.

Now onto your questions. Currently the expression engine supports only plain old CLR properties (including indexers as well). It does not support dynamic objects (via IDynamicMetaObjectProvider), nor DataTables /DataViews/ICustomTypeDescirptor. The underlying extensibility points are there, but we did not have enough resources to implement it for all scenarios. We will do this eventually in some of our next releases.

Until then I can suggest you to look at MicroModels framework for possible way to handle objects of dynamic shape. You can also look at Vladimir's lightweight DataTable (which also generates on the fly
CLR types with properties). Both solutions are for Silverlight, but can be compiled for WPF as well. Alternatively you can take a look into the Automapper framework for a general purpose solution.

Hope this helps,
Stefan Dobrev
the Telerik team

[Guru]

Stefan,
I am impressed that the author of this component is joining this post, kudos! Let me just say, the component is a good idea and has great potential for our application and I look forward to implementing it. For now in test I will research and attempt your suggestions and post back my results. Thanks again for the good input straight from the source. I would imagine that it gets less attention than grids and combobox but it is a component of WPF suite and I would like to see it have at least and end-user guide and be a little friendlier with datatables or more generic objects most perople use... if possible.

[Dimitrina]

Hi,

 Thank you for your feedback. The requested functionality is not in our immediate development plans but we will have shortly a discussion on its future additions.

Regards,
Didie
the Telerik team

[Douw]

Hi Stefan,

I require the same functionality to be able to bind to an ExpandoObject, do you have an ETA on when this will be available?

Regards,

Douw

[Dimitrina]

Hi Douw,

For the time being we do not have any planned modifications on the control. RadExpressionEditor already provides support for dynamic objects with ICustomTypeProvider (.NET 4.5) or ICustomTypeDescriptor implementation. 
My suggestion would be to consider using ICustomTypeProvider instead.

Regards,
Dimitrina
Telerik