我试图将https://docs.microsoft.com/en-us/aspnet/web-api/overview/older-versions/creating-a-web-api-that-supports-crud-operations中的C#代码转换为VB .Net。
我已经创建了如下的接口IProductRepository,
Namespace ProductStore.Models
Interface IProductRepository
Function GetAll() As IEnumerable(Of Product)
Function [Get](ByVal id As Integer) As Product
Function Add(ByVal item As Product) As Product
Sub Remove(ByVal id As Integer)
Function Update(ByVal item As Product) As Boolean
End Interface
End Namespace
然后创建ProductRepository类,如下所示,
Namespace ProductStore.Models
Public Class ProductRepository
Inherits IProductRepository
Private products As List(Of Product) = New List(Of Product)()
Private _nextId As Integer = 1
Public Sub New()
Add(New Product With {.Name = "Tomato soup", .Category = "Groceries", .Price = 1.39D})
Add(New Product With {.Name = "Yo-yo", .Category = "Toys", .Price = 3.75D})
Add(New Product With {.Name = "Hammer", .Category = "Hardware", .Price = 16.99D})
End Sub
Public Function GetAll() As IEnumerable(Of Product)
Return products
End Function
Public Function [Get](ByVal id As Integer) As Product
Return products.Find(Function(p) p.Id = id)
End Function
Public Function Add(ByVal item As Product) As Product
If item Is Nothing Then
Throw New ArgumentNullException("item")
End If
item.Id = Math.Min(System.Threading.Interlocked.Increment(_nextId), _nextId - 1)
products.Add(item)
Return item
End Function
Public Sub Remove(ByVal id As Integer)
products.RemoveAll(Function(p) p.Id = id)
End Sub
Public Function Update(ByVal item As Product) As Boolean
If item Is Nothing Then
Throw New ArgumentNullException("item")
End If
Dim index As Integer = products.FindIndex(Function(p) p.Id = item.Id)
If index = -1 Then
Return False
End If
products.RemoveAt(index)
products.Add(item)
Return True
End Function
End Class
End Namespace
但我收到的行继承IProductRepository的错误为“类只能从其他类继承。”。当我将Inherits更改为Implements时,如下所示 实现IProductRepository
我收到以下错误,
类'ProductRepository'必须实现'Function GetAll()As System.Collections.Generic.IEnumerable(Of Product)'用于接口 'IProductRepository'
和IProductRepository中的其他接口相同。你能帮我解决这个问题。
答案 0 :(得分:1)
您的班级 ProductRepository 应该实现 IProductRepository 这样的接口,
Public Class ProductRepository
Implements IProductRepository
您必须明确使用 Implements 关键字来实现ProductRepository类中的接口方法
Public Function GetAll() As IEnumerable(Of Product) Implements IProductRepository.GetAll
Return products
End Function