Question

我有以下HandleErrorModule课程：

public sealed class HandleErrorModule : IHttpModule {
    private static ILogger _logger;
    private static CustomErrorsSection _section;
    private static Dictionary<HttpStatusCode, String> _views;

    private static CustomErrorsSection CustomErrorsSection { 
      get { 
        if (_section != null) 
          return _section;
        else 
          return WebConfigurationManager.GetWebApplicationSection("system.web/customErrors") as CustomErrorsSection; 
      } 
    }

    private static ILogger Logger { 
      get { return (_logger != null) ? _logger : ObjectFactory.GetInstance<ILogger>(); }
    }

    private static Dictionary<HttpStatusCode, String> Views { 
      get { 
        if (_views != null) 
          return _views;
        else
          return new Dictionary<HttpStatusCode, String> { { HttpStatusCode.NotFound, "NotFound_" }, { HttpStatusCode.InternalServerError, "Internal_" } }; 
       } 
    }

    public void Init(HttpApplication application) {

       // Handle error code.
       // Here I access CustomErrorsSection, Logger and Views properties

    }

获取警告：

字段'HandleErrorModule._views'永远不会被赋值，并且将始终具有其默认值null 字段'HandleErrorModule._section'永远不会被赋值，并且将始终具有其默认值null 字段'HandleErrorModule._logger'永远不会被赋值，并且将始终具有其默认值null

我做错了什么？

Answer 1

信息非常清晰。没有任何成员在任何地方分配值。使用它们的属性是唯一的。

查看代码类型和推测用法，我建议使用参数化构造函数来设置这些字段的值。

Answer 2

我认为您希望这些静态属性可以懒惰地初始化对象。你这样做的方式，他们从不设置私有字段，但继续创建新对象。所以你可能想这样做：

private static Dictionary<HttpStatusCode, String> Views
{
    get
    {
        // when the private field is null, initialize the value
        if (_views == null)
        {
            _views = new Dictionary<HttpStatusCode, String> {
                    { HttpStatusCode.NotFound, "NotFound_" },
                    { HttpStatusCode.InternalServerError, "Internal_" } };
        }

        // and always return the private field
        return _views;
    } 
}

Field ...永远不会被赋值，并且将始终具有其默认值null

2 个答案: