类和静态变量

Question

OutputFormatsBase是用于管理输出格式的基类。 OutputFormats1和OutputFormats2类是从OutputFormatsBase类继承的。

我在OutputFormatsBase类中_listOfObjects了静态变量_listOfObjects的问题，找不到解决方法。

如果我将_listOfObjects静态，则所有内容都可以正常工作，除了OutputFormats1和OutputFormats2类的静态实例是共享的之外，还不好。

有人可以建议如何解决这个问题吗？ 我完全迷路了。

public class OutputFormats1 : OutputFormatsBase
{
    public static readonly OutputFormats1 Bmp = new OutputFormats1 { Value = "BMP", FileExtension = "bmp", Id = 1 };
    public static readonly OutputFormats1 Jpg = new OutputFormats1 { Value = "JPG", FileExtension = "jpg", Id = 2 };
    public static readonly OutputFormats1 Png = new OutputFormats1 { Value = "PNG", FileExtension = "png", Id = 3 };
    public static readonly OutputFormats1 Tiff = new OutputFormats1 { Value = "TIFF", FileExtension = "tif", Id = 4 };
    public override OutputFormatsBase Selected { get; set; }
    public override OutputFormatsBase Default
    {
        get { return Png; }
    }
}

public class OutputFormats2 : OutputFormatsBase
{
    public static readonly OutputFormats2 Pdf = new OutputFormats2 { Value = "PDF", FileExtension = "pdf", Id = 1 };
    public override OutputFormatsBase Selected { get; set; }
    public override OutputFormatsBase Default
    {
        get { return Pdf; }
    }
}

public abstract class OutputFormatsBase
{
     private static readonly List<OutputFormatsBase> _listOfObjects = new List<OutputFormatsBase>();
     public string Value { get; protected internal set; }
     public string FileExtension { get; protected internal set; }
     public int Id { get; protected internal set; }

     public abstract OutputFormatsBase Selected { get; set; }
     public abstract OutputFormatsBase Default { get; }


     protected OutputFormatsBase()
     {
         _listOfObjects.Add(this);
     }


     public bool Validate(string format)
     {
         for (var i = 0; i < _listOfObjects.Count - 1; i++)
         {
             var outputFormats = _listOfObjects[i];
             if (format.ToLower() == outputFormats.Value.ToLower())
             {
                 Selected = outputFormats;
                 return true;
             }
         }
         return false;
     }
 }

Answer 1

您可以尝试这样的事情：

public abstract class OutputFormatsBase<T> where T : OutputFormatsBase
{
 private static readonly List<T> _listOfObjects = new List<T>();

 protected OutputFormatsBase()
 {
  _listOfObjects.Add((T)this);
 }
}

每个模板实例将有一个_listOfObjects实例。

Answer 2

如果使用泛型，则静态值对于每种泛型类型都是唯一的

public class OutputFormats1 : OutputFormatsBase<OutputFormats1> 
{ 
    public static readonly OutputFormats1 Bmp = new OutputFormats1 { Value = "BMP", FileExtension = "bmp", Id = 1 }; 
    public static readonly OutputFormats1 Jpg = new OutputFormats1 { Value = "JPG", FileExtension = "jpg", Id = 2 }; 
    public static readonly OutputFormats1 Png = new OutputFormats1 { Value = "PNG", FileExtension = "png", Id = 3 }; 
    public static readonly OutputFormats1 Tiff = new OutputFormats1 { Value = "TIFF", FileExtension = "tif", Id = 4 }; 
    public override OutputFormatsBase Selected { get; set; } 
    public override OutputFormatsBase Default 
    { 
        get { return Png; } 
    } 
} 

public class OutputFormats2 : OutputFormatsBase<OutputFormats2> 
{ 
    public static readonly OutputFormats2 Pdf = new OutputFormats2 { Value = "PDF", FileExtension = "pdf", Id = 1 }; 
    public override OutputFormatsBase Selected { get; set; } 
    public override OutputFormatsBase Default 
    { 
        get { return Pdf; } 
    } 
} 

public abstract class OutputFormatsBase<T> where T:OutputFormatsBase 
{ 
     private static readonly List<T> _listOfObjects = new List<T>(); 
     public string Value { get; protected internal set; } 
     public string FileExtension { get; protected internal set; } 
     public int Id { get; protected internal set; } 

     public abstract OutputFormatsBase Selected { get; set; } 
     public abstract OutputFormatsBase Default { get; } 


     protected OutputFormatsBase() 
     { 
         _listOfObjects.Add((T)this); 
     } 


     public bool Validate(string format) 
     { 
         for (var i = 0; i < _listOfObjects.Count - 1; i++) 
         { 
             var outputFormats = _listOfObjects[i]; 
             if (format.ToLower() == outputFormats.Value.ToLower()) 
             { 
                 Selected = outputFormats; 
                 return true; 
             } 
         } 
         return false; 
     } 
 }