/// <summary>
/// Indicates whether a navigation would be valid if it were to be performed.
/// </summary>
/// <param name="command">The navigation command to test.</param>
/// <param name="activity">The destination activity, if this is a choice navigation.</param>
/// <returns>True if the navigation would be valid, false otherwise.</returns>
/// <remarks>
/// <para>
/// This makes a partial copy of the activity tree for processing and attempts to
/// perform a navigation on that copy. This may result in poor performance if this
/// is called many times, but the alternative is to duplicate most of the sequencing
/// code with lots of special cases for changes of state that should have happened but
/// could not because of the temporary nature of this request. This makes it a
/// maintenance nightmare, for something that should only rarely be called anyway
/// except in the case of <Mth>LoadTableOfContents</Mth>.
/// </para>
/// <para>
/// The case of <Mth>LoadTableOfContents</Mth> is tough, but steps are taken within
/// that method to reduce the number of calls to this method to a bare minimum.
/// </para>
/// </remarks>
protected bool IsNavigationValid(NavigationCommand command, Activity activity)
{
SeqNav seqNav;
try
{
NavigatorData clone = CloneForNavigationTest();
Activity destination;
if (activity != null)
{
destination = clone.Activities[activity.ActivityId];
}
else
{
destination = null;
}
if (m_packageFormat == PackageFormat.V1p3)
{
seqNav = new Scorm2004SeqNav(clone);
}
else
{
seqNav = new Scorm12SeqNav(clone);
}
seqNav.OverallSequencingProcess(command, destination);
}
catch (SequencingException)
{
// if there was a sequencing exception,
// this is a failure condition.
return(false);
}
return(true);
}
/// <summary>
/// Indicates whether a navigation would be valid if it were to be performed.
/// </summary>
/// <param name="command">The navigation command to test.</param>
/// <param name="activity">The destination activity, if this is a choice navigation.</param>
/// <returns>True if the navigation would be valid, false otherwise.</returns>
/// <remarks>
/// <para>
/// This makes a partial copy of the activity tree for processing and attempts to
/// perform a navigation on that copy. This may result in poor performance if this
/// is called many times, but the alternative is to duplicate most of the sequencing
/// code with lots of special cases for changes of state that should have happened but
/// could not because of the temporary nature of this request. This makes it a
/// maintenance nightmare, for something that should only rarely be called anyway
/// except in the case of <Mth>LoadTableOfContents</Mth>.
/// </para>
/// <para>
/// The case of <Mth>LoadTableOfContents</Mth> is tough, but steps are taken within
/// that method to reduce the number of calls to this method to a bare minimum.
/// </para>
/// </remarks>
protected bool IsNavigationValid(NavigationCommand command, Activity activity)
{
SeqNav seqNav;
try
{
NavigatorData clone = CloneForNavigationTest();
Activity destination;
if(activity != null)
{
destination = clone.Activities[activity.ActivityId];
}
else
{
destination = null;
}
if(m_packageFormat == PackageFormat.V1p3)
{
seqNav = new Scorm2004SeqNav(clone);
}
else
{
seqNav = new Scorm12SeqNav(clone);
}
seqNav.OverallSequencingProcess(command, destination);
}
catch(SequencingException)
{
// if there was a sequencing exception,
// this is a failure condition.
return false;
}
return true;
}
