axis = dataviz.Trellis.ColumnAxis
if(jsonParam['expression'] != None):
    axis.Expression = jsonParam['expression']
if(jsonParam['categoryMode'] != None):
    axis.CategoryMode = Enum.Parse(clr.GetClrType(CategoryMode),jsonParam['categoryMode'])
if(jsonParam['evaluationMode'] != None):
    axis.EvaluationMode = Enum.Parse(clr.GetClrType(AxisEvaluationMode),jsonParam['evaluationMode'])