在vb.net中实现IDictionary接口

时间：2013-10-11 05:34:58

标签： .net vb.net

我正在尝试在VB.net中实现IDictionary接口，但是收到错误。 请帮助我。

Imports System.Collections.Generic

Public Class DataDictionary Implements IDictionary(Of String, Object)
Private _ce As CalcEngine.CalcEngine
Private _dct As Dictionary(Of String, Object)

Public Sub New(ByVal ce As CalcEngine.CalcEngine)
    _ce = ce
    _dct = New Dictionary(Of String, Object)()
End Sub

#Region "IDictionary<string,object> Members"

Public Sub Add(ByVal key As String, ByVal value As Object) Implements Collections.Generic.IDictionary(Of String, Object).Add
    _dct.Add(key, value)
End Sub
Public Function ContainsKey(ByVal key As String) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).ContainsKey
    Return _dct.ContainsKey(key)
End Function
Public ReadOnly Property Keys() As ICollection(Of String) Implements System.Collections.Generic.IDictionary(Of String, Object).Keys
    Get
        Return _dct.Keys
    End Get
End Property
Public Function Remove(ByVal key As String) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).Remove
    Return _dct.Remove(key)
End Function
Public ReadOnly Property Values() As ICollection(Of Object) Implements System.Collections.Generic.IDictionary(Of String, Object).Values
    Get
        Return _dct.Values
    End Get
End Property
Public Function TryGetValue(ByVal key As String, ByRef value As Object) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).TryGetValue
    If _dct.TryGetValue(key, value) Then
        Dim expr = TryCast(value, String)
        If expr IsNot Nothing AndAlso expr.Length > 0 AndAlso expr(0) = "="c Then
            value = _ce.Evaluate(expr.Substring(1))
        End If
        Return True
    End If
    Return False
End Function
Default Public Property Item(ByVal key As String) As Object Implements System.Collections.Generic.IDictionary(Of String, Object).Item
    Get
        Dim value As Object
        If TryGetValue(key, value) Then
            Return value
        End If
        Throw New Exception("invalid index")
    End Get
    Set(ByVal value As Object)
        _dct(key) = value
    End Set
End Property
#End Region


 #Region "ICollection<KeyValuePair<string,object>> Members"

Public Sub Add(ByVal item As KeyValuePair(Of String, Object)) Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Add
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    d.Add(item)
End Sub
Public Sub Clear() Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Clear
    _dct.Clear()
End Sub
Public Function Contains(ByVal item As KeyValuePair(Of String, Object)) As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Contains
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    Return d.Contains(item)
End Function
Public Sub CopyTo(ByVal array As KeyValuePair(Of String, Object)(), ByVal arrayIndex As Integer) Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).CopyTo
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    d.CopyTo(array, arrayIndex)
End Sub
Public ReadOnly Property Count() As Integer Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Count
    Get
        Return _dct.Count
    End Get
End Property
Public ReadOnly Property IsReadOnly() As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).IsReadOnly
    Get
        Return False
    End Get
End Property
Public Function Remove(ByVal item As KeyValuePair(Of String, Object)) As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Remove
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    Return d.Remove(item)
End Function
#End Region


#Region "IEnumerable<KeyValuePair<string,object>> Members"

    Public Function GetEnumerator() As IEnumerator(Of KeyValuePair(Of String, Object)) Implements IEnumerable(Of KeyValuePair(Of String, Object)).GetEnumerator

    Return TryCast(_dct.GetEnumerator(), IEnumerator(Of KeyValuePair(Of String, Object)))
End Function

#End Region

#Region "IEnumerable Members"

Private Function GetEnumerator() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator
    Return TryCast(_dct.GetEnumerator(), System.Collections.IEnumerator)
End Function

#End Region
End Class

当我编译时出现以下错误：

  

错误1类'DataDictionary'必须实现'Function   GetEnumerator（）As IEnumerator（Of KeyValuePair（Of String，Object））'   对于接口'System.Collections.Generic.IEnumerable（Of。）   System.Collections.Generic.KeyValuePair（Of String，   宾语））'。 H：\ Test \ WindowsApplication1 \ WindowsApplication1 \ ProbeDataDictionary.vb 4 16 WindowsApplication1

     

错误3'公共函数GetEnumerator（）As   System.Collections.Generic.IEnumerator（中   System.Collections.Generic.KeyValuePair（Of String，Object））'和   'Private Function GetEnumerator（）As System.Collections.IEnumerator'   不能相互超载，因为它们只是通过返回而不同   类型。 H：\ Test \ WindowsApplication1 \ WindowsApplication1 \ ProbeDataDictionary.vb 96 21 WindowsApplication1

提前致谢。

2 个答案:

答案 0 :(得分：4)

您错过了一个GetEnumerator方法的接口实现声明：

Public Function GetEnumerator() As IEnumerator(Of KeyValuePair(Of String, Object))

应该是

Public Function GetEnumerator() As IEnumerator(Of KeyValuePair(Of String, Object)) Implements IEnumerable(Of KeyValuePair(Of String, Object)).GetEnumerator

的更新 的

好的，您的方法应该如下：

Public Function GetEnumeratorGeneric() As IEnumerator(Of KeyValuePair(Of String, Object)) Implements IEnumerable(Of KeyValuePair(Of String, Object)).GetEnumerator
    Return _dct.GetEnumerator()
End Function

那是因为你不能有两个同名的方法，即使它们实现了不同的接口。

答案 1 :(得分：-1)

以下代码适用于实现IDictionary接口 

Imports System.Collections.Generic

Public Class DataDictionary
Implements IDictionary(Of String, Object)
Private _ce As CalcEngine.CalcEngine
Private _dct As Dictionary(Of String, Object)

Public Sub New(ByVal ce As CalcEngine.CalcEngine)
    _ce = ce
    _dct = New Dictionary(Of String, Object)()
End Sub

'---------------------------------------------------------------
#Region "IDictionary<string,object> Members"

Public Sub Add(ByVal key As String, ByVal value As Object) Implements Collections.Generic.IDictionary(Of String, Object).Add
    _dct.Add(key, value)
End Sub
Public Function ContainsKey(ByVal key As String) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).ContainsKey
    Return _dct.ContainsKey(key)
End Function
Public ReadOnly Property Keys() As ICollection(Of String) Implements System.Collections.Generic.IDictionary(Of String, Object).Keys
    Get
        Return _dct.Keys
    End Get
End Property
Public Function Remove(ByVal key As String) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).Remove
    Return _dct.Remove(key)
End Function
Public ReadOnly Property Values() As ICollection(Of Object) Implements System.Collections.Generic.IDictionary(Of String, Object).Values
    Get
        Return _dct.Values
    End Get
End Property
Public Function TryGetValue(ByVal key As String, ByRef value As Object) As Boolean Implements System.Collections.Generic.IDictionary(Of String, Object).TryGetValue
    If _dct.TryGetValue(key, value) Then
        Dim expr = TryCast(value, String)
        If expr IsNot Nothing AndAlso expr.Length > 0 AndAlso expr(0) = "="c Then
            value = _ce.Evaluate(expr.Substring(1))
        End If
        Return True
    End If
    Return False
End Function
Default Public Property Item(ByVal key As String) As Object Implements System.Collections.Generic.IDictionary(Of String, Object).Item
    Get
        Dim value As Object
        If TryGetValue(key, value) Then
            Return value
        End If
        Throw New Exception("invalid index")
    End Get
    Set(ByVal value As Object)
        _dct(key) = value
    End Set
End Property
#End Region

'---------------------------------------------------------------
#Region "ICollection<KeyValuePair<string,object>> Members"

Public Sub Add(ByVal item As KeyValuePair(Of String, Object)) Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Add
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    d.Add(item)
End Sub
Public Sub Clear() Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Clear
    _dct.Clear()
End Sub
Public Function Contains(ByVal item As KeyValuePair(Of String, Object)) As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Contains
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    Return d.Contains(item)
End Function
Public Sub CopyTo(ByVal array As KeyValuePair(Of String, Object)(), ByVal arrayIndex As Integer) Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).CopyTo
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    d.CopyTo(array, arrayIndex)
End Sub
Public ReadOnly Property Count() As Integer Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Count
    Get
        Return _dct.Count
    End Get
End Property
Public ReadOnly Property IsReadOnly() As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).IsReadOnly
    Get
        Return False
    End Get
End Property
Public Function Remove(ByVal item As KeyValuePair(Of String, Object)) As Boolean Implements System.Collections.Generic.ICollection(Of KeyValuePair(Of String, Object)).Remove
    Dim d = TryCast(_dct, ICollection(Of KeyValuePair(Of String, Object)))
    Return d.Remove(item)
End Function
#End Region

'---------------------------------------------------------------
#Region "IEnumerable<KeyValuePair<string,object>> Members"

Public Function GetEnumerator2() As IEnumerator(Of KeyValuePair(Of String, Object)) Implements IEnumerable(Of KeyValuePair(Of String, Object)).GetEnumerator
    Return TryCast(_dct.GetEnumerator(), IEnumerator(Of KeyValuePair(Of String, Object)))
End Function

#End Region

'---------------------------------------------------------------
#Region "IEnumerable Members"

Private Function GetEnumerator() As System.Collections.IEnumerator Implements System.Collections.IEnumerable.GetEnumerator
    Return TryCast(_dct.GetEnumerator(), System.Collections.IEnumerator)
End Function
#End Region
End Class
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