fix bug

Server/Infrastructure/Repositories/Siger.Middlelayer.AccRepository/Repositories/AutomationFixtureToolsAssemblyRepository.cs

@@ -210,10 +210,13 @@ namespace Siger.Middlelayer.AccRepository.Repositories
                     errors.Add($"{rowIndex},{(int)RequestEnum.FixtureToolNotFound}");
                 }
                 var parentGuid = parent.guid;
-                var exsit = _context.siger_automation_fixture_tools_assembly.FirstOrDefault(q => q.projectId == projectid && q.son == son.guid && q.parent == parentGuid);
-                if (exsit != null)
+                if(son != null && parent != null)
                 {
-                    errors.Add($"{rowIndex},{(int)RequestEnum.DataExist}");
+                    var exsit = _context.siger_automation_fixture_tools_assembly.FirstOrDefault(q => q.projectId == projectid && q.son == son.guid && q.parent == parentGuid);
+                    if (exsit != null)
+                    {
+                        errors.Add($"{rowIndex},{(int)RequestEnum.DataExist}");
+                    }
                 }
                 if (list.Count(q => q.FixtureTool == item.FixtureTool && q.ParentFixtureTool == item.ParentFixtureTool) > 1)
                 {