BaseClass 不能实现 interface.variable 因为它没有匹配的返回类型

Question

EDIT: SOLVED. I am an idiot sometimes. See my self-answer below...

I'm working on the following C# .Net4.5 code using interfaces and polymorphism

---

public interface IFile
{
    List<string> Contents {get;set;}
}

public class File : IFile
{
    public List<string> Contents {get;set;}
}

---

public interface ICommandFile : IFile
{
    new List<ICommandFileLine> Contents {get;set;} /*ICommandFileLine is defined in the code as well, but I don't believe this is pertinent to the issue I am having.*/
}

public class CommandFile : File, ICommandFile
{
    public new List<ICommandFileLine> Contents {get;set;}
}

---

When I try and do the above, the pre-compiler complains:

CommandFile does not implement interface memeber "ICommandFile.Contents". 'File.Contents' cannot implement "ICommandFile.Contents" because it does not have the matching return type of "List[ICommandFileLine]"

Interface member "List ICommandFile.Contents" is not implemented.

I don't understand. I'm using the new keyword, surely this should indicate I wish to encapsulate the base class and define the new variable type?

Answer 1

Try a generic interface - IFile<T> . Then ICommandFile implements IFile<CommandLine>. Get the idea?

Answer 2

接口成员实现不应像您在 CommandFile 类中那样标记为“新”），这意味着实现类中的成员与从接口继承的成员无关。

Answer 3

I realised what I did wrong not 5 minutes after posting:

List[ICommandFile] Contents EQUALS!? No, {get;set;} !

Changed:

new List[ICommandFileLine] Contents = new ListICommandFileLine;

in my local code to:

new List[ICommandFileLine] Contents {get;set;}

How embarrassing...

I'm still relatively new to implementing interfaces and making these mistakes from time to time.