Determing type of DataTable event in C++

I am creating an inheritance model for event handling (particularly for DataTables and XmlNode).

I have a super class called EventManager with the following virtual functions:

DataCha开发者_运维技巧nged(EventArgs *arg)
DataChanging(EventArgs *arg)
DataInserted(EventArgs *arg)
DataInserting(EventArgs *arg)
DataRemoved(EventArgs *arg)
DataRemoving(EventArgs *arg)

and also derived classes DataTableManager and XmlNodeManager.

DataTable event arguments vary (e.g. DataRowChangeEventArgs and DataColumnEventArgs). If the event arg was casted to an EventArgs for the parameter, how can I determine the original type once in the derived class, i.e. how can I know if the parameter passed was originally a DataRowChangeEventArgs or a DataColumnEventArgs?

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Normally, you should invoke derived-class functionality using virtual functions. However, if you really must test for a type, do this:

DataRowChangeEventArgs* foo = dynamic_cast<DataRowChangeEventArgs*>(arg);
if (foo) {
    // is a DataRowChangeEventArgs
}

Of course, you can also roll that into a single line:

if (DataRowChangeEventArgs* foo = dynamic_cast<DataRowChangeEventArgs*>(arg)) {
    // is a DataRowChangeEventArgs
}

(If you've used C# at all, a dynamic_cast on a pointer is pretty much like the as operator in C#---it returns a pointer to the target type if appropriate, otherwise null.)