c# - 如何重载 Collection(Of T) 的 Items 访问器？

Question

下面的代码是用 Vb.Net 写的，但我要求一个 Vb.Net 或 C# 示例，无论在答案中。

---

我有这样一个类型:

Public NotInheritable Class IniKeyCollection : Inherits Collection(Of IniKey)

    Public Sub New()
    End Sub

    Public Shadows Sub Add(ByVal key As IniKey)
    End Sub

    Public Shadows Sub Add(ByVal name As String, ByVal value As String)
    End Sub

    Public Overloads Function Contains(ByVal keyName As String) As Boolean
    End Function

    Public Overloads Function IndexOf(ByVal keyName As String) As Integer
    End Function

End Class

IniKey 是一个具有两个属性的类型:

Public NotInheritable Class IniKey

    Public Property Name As String
    Public Property Value As String

    Private Sub New()
    End Sub

    Public Sub New(ByVal name As String)
        Me.Name = name
        Me.Value = String.Empty
    End Sub

    Public Sub New(ByVal name As String, ByVal value As String)
        Me.Name = name
        Me.Value = value
    End Sub

End Class

我想做的是向 IniKeyCollection 添加一个重载，以通过键名访问 IniKey 元素。

我的意思是，不是默认使用索引:

Dim col As New IniKeyCollection
Dim item As IniKey = col(index:=0)

使用字符串:

Dim col As New IniKeyCollection
Dim item As IniKey = col(keyName:="name")

...然后在内部(尝试)返回与该键名匹配的元素。

我需要为此操作的基本成员是什么？我该怎么做？

Answer 1

您要查找的 C# 语言语法项称为索引器。

class IniKeyCollection : Collection<IniKey>
{

    private IniKey[] arr = new IniKey[100];

    public IniKey this[string name]
    {
        get
        {
            return arr.Where(x => x.Name == name).DefaultIfEmpty(null).Single();
        }
        set
        {
            //Not implemented
        }
    }
}

您可以在以下网址了解更多信息:MSDN - C# Programming Guide (Indexers)