修正無法取得教師目前在線數問題

TEAMModelBI/Controllers/BIHome/OnLineController.cs

@@ -123,7 +123,7 @@ namespace TEAMModelBI.Controllers.BIHome
                 
                 var tchDaysOrderBy = tchDays.OrderBy(o => o.Key).ToList();
                 tchkey = (int)tchDaysOrderBy[tchDaysOrderBy.Count - 1].Key;
-                onTchCnt = (int)tchDaysOrderBy[tchkey].Value;              
+                onTchCnt = (int)tchDaysOrderBy[tchDaysOrderBy.Count - 1].Value;              
             }
             else
             {// 如果redis沒資料去Azure Storage取
@@ -138,7 +138,7 @@ namespace TEAMModelBI.Controllers.BIHome
                     }
                     var tchDaysOrderBy = tchDays.OrderBy(o => o.Key).ToList();
                     tchkey = (int)tchDaysOrderBy[tchDaysOrderBy.Count - 1].Key;
-                    onTchCnt = (int)tchDaysOrderBy[tchkey].Value;
+                    onTchCnt = (int)tchDaysOrderBy[tchDaysOrderBy.Count - 1].Value;
                 }
             }
             // 撈redis記錄的學生在線人數