I am attempting to add several custom fields to a BO. Following the instructions in the tutorial, you need to add GetCustomBindablePropertyDescriptors override for the property. What do you do if you have 4 properties (or any number larger than 1?



A second question is related to best practices. I have a linking table, I.e. it links rows from two different tables, say WidgetsID to a FactorID. I want to be able to show the widgets at a factor, and be able to provide some details about the widget. Is it a good idea to use custom properties in the linking BO to do this. I.e. the linking BO will have three fields, the pk field, the WidgetID field and the FactorID field. Is is a good idea to add a WidgetName and WidgetDescription custom field, that use ExecuteScalar() to retreive the name and description using the current row WidgetID? If it isn't a good idea, why? And is the alternative to use a BO to a view?



Thanks!

You don't need an interface in this case as you would have to re-write the code in every BO that implemented it.  However, you can inherit the BusinessLayer.  Just create your own BO and then when you create a new business object, just change the inherits to your business layer class and it will use all of your modified code and features:

Then when you create a new business object through the Add Item template, you will need to adjust the inherits the first time (you will notice that the only BO code file that has a inherits declaration is in the MyBo.vb file.  This is so the BO Mapper does not overwrite your inherits statement when changed to use your BO class.  It would look like this in this example:

Actually, the reason I was looking at an interface was that I have another class (a user control actually) that would interface with the common functionality of the special BOs. I.e. I need to reference the Interface in the other class, so I can call the known methods (the BOs will all have sequencing functionality, like MoveItemUp, MoveItemDown, etc.). Each BO would implement the methods as needed by the particular table.

What I ended up doing was to just create two variables, one as a BusinessLayer item and one as my interface item (IParentSequencerBO). Then provided a single public property for the BusinessLayer variable, set the interface variable to the same object. It seems to be working great. E.g. below in case my narrative is confusing.



If you have a better idea, I'm all ears.

OK, what is the correct tag for code snippets. Obviously, the one's I'm using are correct.

What you are doing will definitely work.  There are two other things that you could do.  First, tack this on to my first example...create your own interface, as you have, and then associated this interface with your custom BusinessLayer class.  This is more structured and will be much easier to work with as your application grows.

As for your code snippet, I edited your post and then saved and it worked. There could be underlying characters that are being pasted in with your code causing the problem.  One thing to do is to paste it into notepad first then copy it from there.  THis way all special characters are stripped.

That is exactly what I'm doing. I'm going to have half dozen or so BOs that all have this sequencing functionality. With this interface I can build a reusable UI control/component to re-sequence elements within the BO. Though I might suggest that you provide a IBusinessLayer interface in the future. It would make this sort of thing easier. Then I could just inherit that interface for any of my own and life would be grand

I don't think I can explain this properly over the forum, but there is no need for an IBusinessLayer interface.  An interface is not the solution here...you can use the BusinessLayerBase class, which you will find commonly throughout the framework and in typed editors, etc.  This will give you the base functionality and will allow any type of BO to be handed over to a variable or property typed as this...but I still do not see a need for the IBusinessLayer interface. 

I just wrote out a long explanation of why an IBusinessLayer interface would be helpful when I think I get what you are saying about using a concrete class....



So, I create a new class, lets say ParentSequencerBO. This would not hit any tables right (and thus would always have a red X by it in the BO mapper)? it would look something like:







Then I would derive my actual BOs from it:







Then my User control would reference the abstract class ParentSequencerBusinessLayer and I'm good. See, I think you got it across here in the forum (if I'm getting it)!



P.S. the [codesnippet][/codesnippet] isn't working. I double checked for weird characters, pasted into and out of a text editor...but no joy. Maybe it is user permission thing?