Измененена сигнатура функции получения списка для логики курсов и симптомов

Polyclinic/PolyclinicBusinessLogic/BusinessLogics/CourseLogic.cs

@@ -58,14 +58,14 @@ namespace PolyclinicBusinessLogic.BusinessLogics
             return element;
         }
 
-        public List<CourseViewModel>? ReadList(CourseSearchModel? model)
+        public List<CourseViewModel> ReadList(CourseSearchModel? model = null)
         {
             _logger.LogInformation("ReadList. Id:{Id}", model?.Id);
             var list = model == null ? _courseStorage.GetFullList() : _courseStorage.GetFilteredList(model);
             if (list == null)
             {
                 _logger.LogWarning("ReadList return null list");
-                return null;
+                return new List<CourseViewModel>();
             }
             _logger.LogInformation("ReadList. Count:{Count}", list.Count);
             return list;

Polyclinic/PolyclinicBusinessLogic/BusinessLogics/DiagnoseLogic.cs

@@ -58,14 +58,14 @@ namespace PolyclinicBusinessLogic.BusinessLogics
             return element;
         }
 
-        public List<DiagnoseViewModel>? ReadList(DiagnoseSearchModel? model)
+        public List<DiagnoseViewModel> ReadList(DiagnoseSearchModel? model = null)
         {
             _logger.LogInformation("ReadList. Name:{Name} Id:{Id}, UserId:{UserId}", model?.Name, model?.Id, model?.UserId);
             var list = model == null ? _diagnoseStorage.GetFullList() : _diagnoseStorage.GetFilteredList(model);
             if (list == null)
             {
                 _logger.LogWarning("ReadList return null list");
-                return null;
+                return new List<DiagnoseViewModel>();
             }
             _logger.LogInformation("ReadList. Count:{Count}", list.Count);
             return list;

Polyclinic/PolyclinicBusinessLogic/BusinessLogics/SymptomLogic.cs

@@ -58,14 +58,14 @@ namespace PolyclinicBusinessLogic.BusinessLogics
             return element;
         }
 
-        public List<SymptomViewModel>? ReadList(SymptomSearchModel? model)
+        public List<SymptomViewModel> ReadList(SymptomSearchModel? model = null)
         {
             _logger.LogInformation("ReadList. Name:{Name} Id:{Id}", model?.Name, model?.Id);
             var list = model == null ? _symptomStorage.GetFullList() : _symptomStorage.GetFilteredList(model);
             if (list == null)
             {
                 _logger.LogWarning("ReadList return null list");
-                return null;
+                return new List<SymptomViewModel>();
             }
             _logger.LogInformation("ReadList. Count:{Count}", list.Count);
             return list;

Polyclinic/PolyclinicContracts/BusinessLogicsContracts/ICourseLogic.cs

@@ -6,7 +6,7 @@ namespace PolyclinicContracts.BusinessLogicsContracts
 {
     public interface ICourseLogic
     {
-        List<CourseViewModel>? ReadList(CourseSearchModel? model);
+        List<CourseViewModel> ReadList(CourseSearchModel? model = null);
         CourseViewModel? ReadElement(CourseSearchModel model);
         bool Create(CourseBindingModel model);
         bool Update(CourseBindingModel model);

Polyclinic/PolyclinicContracts/BusinessLogicsContracts/IDiagnoseLogic.cs

@@ -6,7 +6,7 @@ namespace PolyclinicContracts.BusinessLogicsContracts
 {
     public interface IDiagnoseLogic
     {
-        List<DiagnoseViewModel>? ReadList(DiagnoseSearchModel? model);
+        List<DiagnoseViewModel> ReadList(DiagnoseSearchModel? model = null);
         DiagnoseViewModel? ReadElement(DiagnoseSearchModel model);
         bool Create(DiagnoseBindingModel model);
         bool Update(DiagnoseBindingModel model);

Polyclinic/PolyclinicContracts/BusinessLogicsContracts/ISymptomLogic.cs

@@ -6,7 +6,7 @@ namespace PolyclinicContracts.BusinessLogicsContracts
 {
     public interface ISymptomLogic
     {
-        List<SymptomViewModel>? ReadList(SymptomSearchModel? model);
+        List<SymptomViewModel> ReadList(SymptomSearchModel? model = null);
         SymptomViewModel? ReadElement(SymptomSearchModel model);
         bool Create(SymptomBindingModel model);
         bool Update(SymptomBindingModel model);

Polyclinic/PolyclinicWebAppImplementer/Controllers/DiagnosesController.cs

@@ -19,7 +19,7 @@ namespace PolyclinicWebAppImplementer.Controllers
         [HttpGet]
         public IActionResult Index()
         {
-            List<DiagnoseViewModel> diagnoses = _diagnoseLogic.ReadList(null);
+            List<DiagnoseViewModel> diagnoses = _diagnoseLogic.ReadList();
             if (diagnoses == null)
             {
                 diagnoses = new();