重构项目结构，移除Assignment相关功能，优化Submission模块

TechHelper.Client/Services/CommonService.cs

@@ -0,0 +1,47 @@
+using Entities.Contracts;
+using Entities.DTO;
+using System.Net.Http.Json;
+using TechHelper.Client.HttpRepository;
+
+namespace TechHelper.Client.Services
+{
+
+	public class CommonService : ICommonService
+	{
+		private readonly HttpClient _client;
+		private readonly IAuthenticationClientService _authenticationClientService;
+
+		public CommonService(HttpClient client, IAuthenticationClientService authenticationClientService)
+		{
+			_client = client;
+			_authenticationClientService = authenticationClientService;
+		}
+		public async Task<List<TypeCommonDto>> GetCommonTypesAsync(TypeNameType typeNameType, Guid? SubjectId = null)
+		{
+
+			switch (typeNameType)
+			{
+				case TypeNameType.Subject:
+					{
+						var response = await _client.GetAsync("subject");
+						var result = await response.Content.ReadFromJsonAsync<List<TypeCommonDto>>();
+						return result;
+					}
+				case TypeNameType.ExamType:
+					{
+						var response = await _client.GetAsync("exam-type");
+						var result = await response.Content.ReadFromJsonAsync<List<TypeCommonDto>>();
+						return result;
+					}
+				case TypeNameType.QuestionType:
+					{
+						var response = await _client.GetAsync("question-type");
+						var result = await response.Content.ReadFromJsonAsync<List<TypeCommonDto>>();
+						return result;
+					}
+			}
+
+			throw new NotImplementedException();
+		}
+	}
+}