LINQ to Objects .Distinct() 不提取不同的对象

Question

我有两种方法可以对客户进行模糊搜索。一种是缩写名称，另一种是客户的全名。当我获取这两个结果集然后将它们合并在一起时(我已经阅读了几个地方应该删除不同的值)我得到重复。认为我需要做的就是调用.Distinct()对此的方法，我也仍然得到重复。我是否需要在我的客户对象中实现一些比较功能？
我的代码:

        Dim shortNameMatch As List(Of ICustomer) = CustomerLibrary.GetCustomersByShortName(term)
        Dim custNameMatch As List(Of ICustomer) = CustomerLibrary.GetCustomersByCustName(term)
        Dim allMatch = (From a In (From s In shortNameMatch Select s).Union(From c In custNameMatch Select c) Select a).Distinct()

Answer 1

您需要创建一个相等比较器并在 Union 中使用它或 Distinct :

Public Class MyComparer
    Implements IEqualityComparer(Of ICustomer)

    Public Overloads Function Equals(ByVal x As ICustomer, ByVal y As ICustomer) _
        As Boolean Implements _
        System.Collections.Generic.IEqualityComparer(Of ICustomer).Equals
        Return ((x.id = y.id) AndAlso (x.title = y.title))
    End Function
    Public Overloads Function GetHashCode(ByVal obj As ICustomer) _
        As Integer Implements _
        System.Collections.Generic.IEqualityComparer(Of ICustomer).GetHashCode
        Return Me.GetHashCode()
    End Function
End Class

使用示例:

Dim allMatch = shortNameMatch.Union(custNameMatch).Distinct(New MyComparer())
Dim allMatch = shortNameMatch.Union(custNameMatch, New MyComparer())