private bool LayoutRuleMaximumSpacingInformation(BeamSystem beamSystem)
{
    //get the layoutRule of the beamsystem
    Autodesk.Revit.DB.LayoutRule layoutRule = beamSystem.LayoutRule;

    string message = "BeamSystem layout rule : " + layoutRule;

    //create a new instance of the LayoutRuleClearSpacing class 
    LayoutRuleMaximumSpacing myLayoutRuleMaximumSpacing =
                        new LayoutRuleMaximumSpacing(10.0);

    //set the new layoutRule to the beamsystem
    beamSystem.LayoutRule = myLayoutRuleMaximumSpacing;

    LayoutRuleMaximumSpacing maximunSpacing = beamSystem.LayoutRule as LayoutRuleMaximumSpacing;
    if (null == maximunSpacing)
    {
        return false;
    }
    //try to get the property value of the beamsystem LayoutRule
    double spacing = maximunSpacing.Spacing;

    message += "\nNew BeamSystem layout rule: " + maximunSpacing;
    message += "\nNew BeamSystem maximum spacing: " + spacing;

    TaskDialog.Show("Revit",message);

    return true;
}

Private Function LayoutRuleMaximumSpacingInformation(beamSystem As BeamSystem) As Boolean
    'get the layoutRule of the beamsystem
    Dim layoutRule As Autodesk.Revit.DB.LayoutRule = beamSystem.LayoutRule

    Dim message As String = "BeamSystem layout rule : " & layoutRule.ToString()

    'create a new instance of the LayoutRuleClearSpacing class 
    Dim myLayoutRuleMaximumSpacing As New LayoutRuleMaximumSpacing(10.0)

    'set the new layoutRule to the beamsystem
    beamSystem.LayoutRule = myLayoutRuleMaximumSpacing

    Dim maximunSpacing As LayoutRuleMaximumSpacing = TryCast(beamSystem.LayoutRule, LayoutRuleMaximumSpacing)
    If maximunSpacing Is Nothing Then
        Return False
    End If
    'try to get the property value of the beamsystem LayoutRule
    Dim spacing As Double = maximunSpacing.Spacing

    message += vbLf & "New BeamSystem layout rule: " & maximunSpacing.ToString()
    message += vbLf & "New BeamSystem maximum spacing: " & spacing

    TaskDialog.Show("Revit", message)

    Return True
End Function