From eb8eb43ea372ecf55f39fb288ea4610495f8366a Mon Sep 17 00:00:00 2001
From: Jicheng Lu <103353@smsassist.com>
Date: Wed, 2 Jul 2025 13:12:04 -0500
Subject: [PATCH] handle null string

---
 .../BotSharp.Plugin.ChartHandler/Functions/PlotChartFn.cs       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Plugins/BotSharp.Plugin.ChartHandler/Functions/PlotChartFn.cs b/src/Plugins/BotSharp.Plugin.ChartHandler/Functions/PlotChartFn.cs
index 02ea76b6..43c917d2 100644
--- a/src/Plugins/BotSharp.Plugin.ChartHandler/Functions/PlotChartFn.cs
+++ b/src/Plugins/BotSharp.Plugin.ChartHandler/Functions/PlotChartFn.cs
@@ -49,7 +49,7 @@ public class PlotChartFn : IFunctionCallback
         ]);
 
         var obj = response.JsonContent<LlmContextOut>();
-        message.Content = obj?.GreetingMessage ?? "Here is the chart you ask for:";
+        message.Content = obj?.GreetingMessage.IfNullOrEmptyAs("Here is the chart you ask for:");
         message.RichContent = new RichContent<IRichMessage>
         {
             Recipient = new Recipient { Id = convService.ConversationId },