在asp.net core中使用类似Application的服务的实现

<title>@ViewBag.Title - @HttpContext.Current.Application["SystemTitle"]</title>
<meta name="keywords" content="@HttpContext.Current.Application["SystemKeywords"]" />

 public interface IApplicationSettingService
 {
  string GetSettingValue(string settingKey);

  string SetSettingValue(string settingKey, string settingValue);

  int AddSettings(Dictionary<string, string> dictionary);
 }

 public class ApplicationSettingInMemoryService : IApplicationSettingService
 {
  private readonly ConcurrentDictionary<string, string> _settingDictionary = new ConcurrentDictionary<string, string>();

  public int AddSettings(Dictionary<string, string> dictionary)
  {
   if (dictionary != null && dictionary.Count > 0)
   {
    foreach (var item in dictionary)
    {
     _settingDictionary[item.Key] = item.Value;
    }
   }
   return _settingDictionary.Count;
  }

  public string GetSettingValue(string settingKey)
  {
   _settingDictionary.TryGetValue(settingKey, out var val);
   return val;
  }

  public string SetSettingValue(string settingKey, string settingValue)
  {
   _settingDictionary[settingKey] = settingValue;
   return settingValue;
  }
 }

services.TryAddSingleton<IApplicationSettingService, ApplicationSettingInMemoryService>();

@using ActivityReservation.Services
@inject IApplicationSettingService applicationSettings
/ 此处省略 N 行代码 ... /
<title>@($"{ViewBag.Title} -- {applicationSettings.GetSettingValue("SystemTitle")}") </title>
<meta name="keywords" content="@(applicationSettings.GetSettingValue("SystemKeywords"))" />