private bool LayoutRuleFixedDistanceInformation(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 
    LayoutRuleFixedDistance myLayoutRuleFixedDistance =
                new LayoutRuleFixedDistance(10.0, BeamSystemJustifyType.End);

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

    LayoutRuleFixedDistance fixedDistance = beamSystem.LayoutRule as LayoutRuleFixedDistance;
    if (null == fixedDistance)
    {
        return false;
    }
    //try to get the property value of the beamsystem LayoutRule
    BeamSystemJustifyType justifyType = fixedDistance.JustifyType;

    double spacing = fixedDistance.Spacing;

    message += "\nNew BeamSystem layout rule: " + fixedDistance;
    message += "\nNew BeamSystem spacing: " + spacing;
    message += "\nNew BeamSystem justification: " + justifyType;

    TaskDialog.Show("Revit",message);

    return true;
}

Private Function LayoutRuleFixedDistanceInformation(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 myLayoutRuleFixedDistance As New LayoutRuleFixedDistance(10.0, BeamSystemJustifyType.[End])

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

    Dim fixedDistance As LayoutRuleFixedDistance = TryCast(beamSystem.LayoutRule, LayoutRuleFixedDistance)
    If fixedDistance Is Nothing Then
        Return False
    End If
    'try to get the property value of the beamsystem LayoutRule
    Dim justifyType As BeamSystemJustifyType = fixedDistance.JustifyType

    Dim spacing As Double = fixedDistance.Spacing

    message += vbLf & "New BeamSystem layout rule: " & fixedDistance.ToString()
    message += vbLf & "New BeamSystem spacing: " & spacing
    message += vbLf & "New BeamSystem justification: " & justifyType

    TaskDialog.Show("Revit", message)

    Return True
End Function