This collection manages the particle parameters of a particle system. All parameters must have a unique name ( or empty strings are not allowed).

New particle parameters can be added using the methods AddUniformT(String) and AddVaryingT(String). If a particle parameter with the given name already exists, AddUniformT(String) returns the existing parameter and does nothing else - even if the existing parameter is varying. If a particle parameter with the given name already exists, AddVaryingT(String) returns the existing parameter if it is varying. But if the existing parameter is uniform, AddVaryingT(String) replaces the existing parameter. - This means: Calling AddUniformT(String) and AddVaryingT(String) multiple times is safe. Varying parameters have higher priority and replace uniform parameters.

The generic methods AddUniformT(String), AddVaryingT(String) and GetT(String) throw an ParticleSystemException if a particle parameter with the given name exists but the particle parameter type is different. The method GetUncheckedT(String) is the same as GetT(String, Boolean), except that it does not throw an exception. It returns if the requested particle parameter does not exist or the type does not match.

Parameter Inheritance:
Per default, the Get() methods also search for uniform (but not varying) parameters in the particle parameter collections of parent particle systems if a parameter is not found in this collection. This means that uniform parameters are automatically inherited by child particle systems. Note that enumerating the collection (using GetEnumerator) only returns the locally stored particle parameters, i.e. inherited parameters are not included in the enumeration.

Objects that manipulate particle parameters can hold references to the IParticleParameter instances. The event Changed is raised when the collection is modified. In this case any references to particle parameters get invalid. - The particle parameters could have been replaced or removed. (ParticleEffectors do not need to subscribe to the Changed event. They will automatically be updated by the ParticleSystem that owns them.)

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