In the last (and first) post of this series we discussed how to create a typed dataset. Now that we have our dataset we need to see how to use it.

But before we go into the details, I want to explain something that I stumbled upon in my research. There is a serious bug in the implementation of the dataset generator. It effects retrieving and manipulating childrows when you are dealing with related tables.

After a great deal of hair pulling, self doubt, and serious coffee consumption, I finally found a series of blog posts that ended up leading me here. The bug has been confirmed and will be released: “thanks again for reporting this. We fixed this problem and the fix will be available in the next Visual Studio release.”

Description

When you create a typed DataSet using the class-designer of VS.NET with a parent- and a child-table, a method is generated on the parentrow-class which should return the childrows. This method uses DataRow.GetChilds with the name of the relationship. This method returns a parentrow-array instead of a childrow-array. The generated method casts it to a childrow-array and thus causes a InvalidCastException.