处理年级ID出现负数的情况

TEAMModelOS/Controllers/Analysis/ClassAnalysisController.cs

@@ -418,7 +418,7 @@ namespace TEAMModelOS.Controllers.Analysis
             {
                 foreach (string gId in record.grade)
                 {
-                    if (!grades.Contains(gId))
+                    if (!grades.Contains(gId) && int.Parse(gId) >= 0)
                     {
                         grades.Add(gId);
                     }