如何提供ProjectItem.get_FileNames(i)的实现？

Question

我正在尝试设置一个很好的REPL，用于移动csharp代码。但是，我似乎无法编写EnvDTE.ProjectItem (接口)实现的代码。

接口上的错误行为属性的定义在索引器中为：

string FileNames[short i] {get;}

基于这个职位我试过

[IndexerName("FileNames")]
string ProjectItem.this[short i] {get{return "test";}}

在显式接口声明中，'this‘不是接口的成员

[IndexerName("FileNames")]
public string this[short i] {get{return "test";}}

返回访问器'UserQuery.ProjectItemFake.thisshort.get‘不能实现'UserQuery.ProjectItemFake’类型的接口成员‘EnvDTE.ProjectItem.get_FileNames(简称)’。使用显式接口实现.

[IndexerName("FileNames")]
string ProjectItem.this[short i] {get{return "test";}}

在显式接口声明中返回'this‘不是接口的成员

我对.net语言完全开放，基本理解是C#、F#或VB.net。

您能以某种方式用EnvDTE.ProjectItem编写.net接口的实现吗？

Answer 1

只需实现方法get_FileNames(short i)。

属性(包括索引属性)实际上被转换为像get_PropertyName和set_PropertyName这样的方法。在大多数情况下，编译器不允许您实现这样的属性，只是因为它依赖于成员元数据。命名索引器在C#中不可用，但在VB.NET中可用，我认为接口是用VB.NET定义的(它们是也可在F#中获得，但我不确定它们是否兼容)。

C#编译器允许您将VB.NET索引属性实现为get_PropertyName(Whatever x)，因为这是实现这些属性的唯一方法。我试过了，而且对我有用。

完整的C#实现如下：

class ProjectItemMock : ProjectItem{
    public bool SaveAs(string newFilename) { return false;}
    public EnvDTE.Window Open(string name) { return null;}
    public void Remove() {}
    public void ExpandView(){}
    public void Save(string filename){}
    public void Delete(){}
    public bool IsDirty {get;set;}
    public string get_FileNames(short index) {return "test";}
    public short FileCount {get;set;}
    public string Name{get;set;}
    public string Kind { get; set; }
    public EnvDTE.ProjectItems Collection {get;set;}
    public EnvDTE.Properties Properties {get;set;}
    public EnvDTE.DTE DTE{get;set;}
    public EnvDTE.ProjectItems ProjectItems { get; set; }
    public bool get_IsOpen(string s) { return false;}
    public object Object { get; set; }
    public object get_Extender(string s) {return null;}
    public object ExtenderNames { get; set; }
    public string ExtenderCATID { get; set; }
    public bool Saved { get; set; }
    public EnvDTE.ConfigurationManager ConfigurationManager { get; set; }
    public EnvDTE.FileCodeModel FileCodeModel { get; set; }
    public EnvDTE.Document Document { get; set; }
    public EnvDTE.Project SubProject { get; set; }
    public EnvDTE.Project ContainingProject { get; set; }
}

Answer 2

我怀疑格雷格是正确的，因为在F#中使用了类似的方法

下面是一个完整的接口实现，它似乎工作得很好。

let makeProjectItem name kind fileNames fcm = 
    let name = ref name
    let isDirty = ref  false
    let saved = ref false
    let empty = null
    let fileNames:string[] = fileNames
    { 
        new EnvDTE.ProjectItem
        with
            member this.FileNames with get(index:int16) = fileNames.[ int(index)]
            member this.Open(viewKind) = null
            member this.Remove() = ()
            member this.get_IsOpen s = false
            member this.Kind = kind
            member this.ProjectItems = null
            member this.ExpandView() = ()
            member this.DTE = null
            member this.Properties = null
            member this.Object = null
            member this.Collection = null
            member this.Saved with get() = !saved and set(value) = saved := value
            member this.ExtenderCATID = null
            member this.Name 
                with get() = !name
                and set(value) = name := value
            member this.get_Extender (s:string) : obj = null
            member this.FileCount = 1s
            member this.SaveAs nfn = false
            member this.ContainingProject = null
            member this.SubProject = null
            member this.Document = null
            member this.Save fn = ()
            member this.IsDirty with get() = !isDirty  and set(value) = isDirty := value
            member this.Delete () = ()
            member this.get_FileCodeModel():EnvDTE.FileCodeModel = fcm
            member this.get_ExtenderNames() = null
            member this.get_ConfigurationManager () = null
    }