Добавьте файлы проекта.

Yuna.Website/Yuna.Website.Server/Services/PropService/IPropService.cs

@@ -0,0 +1,15 @@
+using Yuna.Website.Server.Model;
+
+namespace Yuna.Website.Server.Services.DeviceSkillService
+{
+    public interface IPropService
+    {
+        public Task<Prop?> GetById(long id);
+        public Task<Prop?> GetByPropName(string value);
+        public Task<IReadOnlyList<Prop>> GetList();
+        public Task<Prop?> Create(Prop value);
+        //public Task<User?> Update(User user);
+        public Task<Prop?> Delete(long id);
+        public Task<IReadOnlyList<Prop>?> GetByIds(long[] ids);
+    }
+}