string.IsNullOrEmpty(activity.progress)

TEAMModelOS.SDK/Models/Service/GroupListService.cs

@@ -546,7 +546,7 @@ namespace TEAMModelOS.SDK.Models.Service
                 foreach (MQActivity activity in datas)
                 {
                     //已经完结的不再允许加入,还未开始的。
-                    if (activity.progress.Equals("finish") || activity.progress.Equals("pending"))
+                    if (string.IsNullOrEmpty(activity.progress)|| activity.progress.Equals("finish") || activity.progress.Equals("pending"))
                     {
                         continue;
                     }

TEAMModelOS.SDK/Models/Service/StuListService.cs

@@ -63,7 +63,7 @@ namespace TEAMModelFunction
                 foreach (MQActivity activity in datas)
                 {
                     //已经完结的不再允许加入
-                    if (activity.progress.Equals("finish") || activity.progress.Equals("pending"))
+                    if (string.IsNullOrEmpty(activity.progress)|| activity.progress.Equals("finish") || activity.progress.Equals("pending"))
                     {
                         continue;
                     }