How to get row count of a DataRelation?

[PeterZ]

If you have two dataTables and a dataRelation how would you get the row
count of the dataRelation?

Lets use the obligatory simpleton example - A strongly typed dataset with an
Authors and Books table and a dataRelation between the two.

ie:
myDataSet.Authors
myDataSet.Books
myDataSet.relBooksByAuthor

Now you bind a listbox to the Authors and a dataGrid to the dataRelation.
The grid now shows only the books by the currently selected author.
Mindblowing stuff I know, but just try to stay with me on this one

Ok, now how would you get the row count of the books by the currently
selected author? Surely this must be a property of the dataRelation object?
I mean it must know how many rows its filtering at any given time?

I tried looking for a Rows.Count property in a dataRelation but there isn't
any, ie:

myDataSet.relations["relBooksByAuthor"].Rows.Count? not there!

If I get the row count of myDataSet.Books.Rows.Count I always get the total
number in the whole table, not the filtered count.

Surely this must be a nobrainer?
Can anyone shed light?


Thanks,
PeterZ

 

[Dave Fancher]

Take a look at the GetChildRows() method of the DataRow.

http://msdn.microsoft.com/library/d...rfsystemdatadatarowclassgetchildrowstopic.asp