NET统计图使用Chartlet控件绑定数据为空时页面报错

NET统计图使用Chartlet控件绑定数据为空时页面出错

Chartlet4.AppearanceStyle = FanG.Chartlet.AppearanceStyles.HBar_2D_Aurora_FlatCrystal_Glow_NoBorder;

        Chartlet4.XLabels.RotateAngle = 0;

        Chartlet4.ChartTitle.Text = "HBar-Pareto (横向柱图-柏拉图)";

        Chartlet4.Fill.TextureEnable = true;

        Chartlet4.BindChartData(ds);

当ds为空时页面出错，怎么办？
我是新手，请大家多多指教！
------解决方案--------------------

 if (ds != null)

            {

                Chartlet4.AppearanceStyle = FanG.Chartlet.AppearanceStyles.HBar_2D_Aurora_FlatCrystal_Glow_NoBorder;

                Chartlet4.XLabels.RotateAngle = 0;

                Chartlet4.ChartTitle.Text = "HBar-Pareto (横向柱图-柏拉图)";

                Chartlet4.Fill.TextureEnable = true;

                Chartlet4.BindChartData(ds);

            }