Editing Nested DataGrids in ASP.NET
If you have your heart set on using a DataList with a nested DataGrid, my good friend Joe Shook demonstrated a functional way to do this as well.
Define a Web Form with a DataList. In that form, implement your editing events. Each time the DataList.ItemCreated event fires, the ItemCreated event will send an argument containing a DataListItem. The DataListItem contains the dynamically created UserControl. Using the event argument, call e.Item.Find("uc1"), where uc1 is your UserControl's ID, to obtain a reference to the template-created UserControl. If the Find returns the UserControl, request the DataGrid on that UserControl and manually re-associate your edit event handlers with the DataGrid by calling AddHandler.
There are so many things I like about programming in .NET that the few things that seem out of whack don't bother me too much. From my own experience, conversations, and newsgroups, it appears that nesting a DataGrid in a DataList doesn't work quite the way one would expect. Perhaps this is by design or is a bug; we may never know.
Through experimentation, it appears that a nested DataGrid's edit events aren't restored when the DataGrid is nested in a DataList. In this article, Part 3 of 3, I demonstrated a workaround for the nonexistent edit behavior that excludes the DataList from the equation, requiring you to load a UserControl containing a DataGrid for each object in the master data source—this is the data used as the DataList's data source. As an alternative, you can use the DataList with a nested DataGrid, but you will have to manually find the dynamically created DataGrids defined in the DataList's templates and re-associate the DataGrid event handlers in the DataList's ItemCreated event. The later approach, while not shown here, has been demonstrated to work.
I suspect from conversations I have had that Microsoft is aware of this relatively minor problem and a more permanent solution will be forthcoming.
About the Author
Paul Kimmel is a software architect, writer, and columnist for codeguru.com. Look for his recent book Visual Basic .NET Power Coding from Addison-Wesley. Paul Kimmel is available to help design and build your .NET solutions and can be contacted at firstname.lastname@example.org.
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