Datagrid - change datasource at runtime

[AHint]

I have a datagrid that I change the datasource for at runtime. It is always bound to a strongly typed collection. If I bind to a collection, then bind to another collection with a larger number of items I get an 'Error when committing changes to original data store'. I believe that somehow the binding isn't resetting properly.

I am using:

dgdNominalPostingsWithHeld.SetDataBinding(typedObject, "typedObjectCollection");

when binding.

Have tried setting datasource to null first and refreshing but no luck.

Any ideas?