StrataFrame Forum » StrataFrame Application Framework - V1 » Business Objects and Data Access (How do I?) » Null-value mishandled in BOM-generated code

Null-value mishandled in BOM-generated code

Kirk M Sherhart — Wed, 08 Apr 2009 09:15:16 GMT

I have a simple table with a nullable numeric field JOB_TYPE, which BOM sees as a System.Decimal value. If I set BOM to use "Nullable Generics" AND to create property accessing event for the field, I get the following BOM-generated code for the field accessor
[code] public Nullable<System.Decimal> JOB_TYPE
{
get
{
object loValue;
PeopleBOFieldAccessingEventArgs e;
Nullable<System.Decimal> loReturn;
loValue = this.CurrentRow["JOB_TYPE"];
if (loValue == DBNull.Value)
{
loReturn = (Nullable<System.Decimal> )null;
}
else
{
loReturn = new Nullable<System.Decimal> ((System.Decimal)loValue);
}
e = new PeopleBOFieldAccessingEventArgs(PeopleBOFieldNames.JOB_TYPE, loReturn);
this.OnFieldPropertyAccessing(this, e);
return new Nullable<System.Decimal> ((System.Decimal)(e.ValueToReturn)); <===BOOM!
}
set
{...}
[/code]
If JOB_TYPE is null, loReturn becomes a null of type decimal?, but is cast (boxed) into a null of type object for the eventargs. After the event is processed (there is no code in the event itself), the value of e.ValueToReturn is a null of type object, which causes the exception when attempting the cast to System.Decimal.

If this a "bug" or "feature"?

RE: Null-value mishandled in BOM-generated code

Trent L. Taylor — Wed, 08 Apr 2009 09:15:16 GMT

I have not yet had a chance to look at this...sorry for the delay. I have added it to the list, so we are making progress! :)

The last two weeks have been crazy busy around here....so sorry for the delay.

RE: Null-value mishandled in BOM-generated code

Kirk M Sherhart — Mon, 06 Apr 2009 09:59:04 GMT

Hi Trent

I've attached some code/text that illustrates the problem. I created a simple, 2-field table with a single record of value (1, null). I generated the BO (see included BOM properties screenshot, etc.) I've included the BOM-generated code for the object. I created a simple form with a button that executes the included code (a simple retrieval and access of the nullable field value.) Clicking the button causes the BOM-generated code for the NULL_TEST_VALUE field accessor to throw a NullReferenceException.

Hope this helps you to track down the problem.

RE: Null-value mishandled in BOM-generated code

Trent L. Taylor — Sat, 04 Apr 2009 13:01:54 GMT

Please send me a sample. Not able to reproduce in the same fashion. A workaround in any case is to get this the way that you like then go back into the BO mapper and use a Custom Code option. Paste the adjusted code into the Customer Code section so that when the BO is rebuilt through the mapper your changes don't get overwritten. But I would still like to see a sample when possible.