COM collections are a way to support groups of related COM
objects that can be iterated over. A collection is itself an interface with a read-only
Count property and an
Item method to
retrieve a single item from the collection.
Item method is indexed, which means that it requires an
argument that specifies which item in the collection is being requested. The data type
of the index is a data type specified by the server that supports the collection.
Although integer indices are common, the index could also be a text value. Often, the
return value from the
Item method is itself an interface. Like all
interfaces, release this interface when you are finished with it.
This example iterates through the members of a collection. Each member of the
collection is itself an interface (called
Plot and represented by a
MATLAB® COM object called
hPlot). In particular, this example
iterates through a collection of
Plot interfaces, invokes the
Redraw method for each interface, and then releases each
hCollection = hControl.Plots; for i = 1:hCollection.Count hPlot = invoke(hCollection,'Item', i); Redraw(hPlot) release(hPlot); end; release(hCollection);