Mike Saltzman said:

The number of child rows is not really the deciding factor here. It's how efficient the data source is at retrieving those rows.

If you use UltraDataSource or a BindingList<T>, it will be fine.

But if you are using a DataSet, the DataSet will loop through every row in the child table every time you try to get the child rows for any particular parent row.

I see.  My child collection happens to be a BindingList<T> :)

The number of child rows is not really the deciding factor here. It's how efficient the data source is at retrieving those rows.

If you use UltraDataSource or a BindingList<T>, it will be fine.

But if you are using a DataSet, the DataSet will loop through every row in the child table every time you try to get the child rows for any particular parent row.

Mike Saltzman said:

Note that in order to determine whether a parent row has child rows, the grid has to ask the BindingManager to retrieve the child rows collection. This could cause some performance issues, depending on the data source (which is why the grid does not do this by default).

 

Thanks for the heads-up!

In my particular scenario though, the child collection will only contain a couple of rows at most.

Steve Smith said:

Using the Ultra Grid designer or in code you have to set the override expansion indicator property of the band in question:

Band.Override.ExpansionIndicator = ShowExpansionIndicator.CheckOnDisplay

Perfect, thanks

Note that in order to determine whether a parent row has child rows, the grid has to ask the BindingManager to retrieve the child rows collection. This could cause some performance issues, depending on the data source (which is why the grid does not do this by default).