Enumerable.Union produces the set union of two sequences by using a specified IEqualityComparer(Of T).
Imports System
Imports System.Linq
Imports System.Collections.Generic
Public Class Item
Public Property Name As String
Public Property Code As Integer
End Class
Public Class ItemComparer
Implements IEqualityComparer(Of Item)
Public Function Equals1(ByVal x As Item, ByVal y As Item) As Boolean Implements IEqualityComparer(Of Item).Equals
If x Is y Then Return True
If x Is Nothing OrElse y Is Nothing Then Return False
Return (x.Code = y.Code) AndAlso (x.Name = y.Name)
End Function
Public Function GetHashCode1(ByVal product As Item) As Integer Implements IEqualityComparer(Of Item).GetHashCode
If product Is Nothing Then Return 0
Dim hashItemName = If(product.Name Is Nothing, 0, product.Name.GetHashCode())
Dim hashItemCode = product.Code.GetHashCode()
Return hashItemName Xor hashItemCode
End Function
End Class
Public Class Example
Public Shared Sub Main()
Dim storeA() As Item =
{New Item With {.Name = "apple", .Code = 9},
New Item With {.Name = "orange", .Code = 4}}
Dim storeB() As Item =
{New Item With {.Name = "apple", .Code = 9},
New Item With {.Name = "orange", .Code = 4}}
Dim union = storeA.Union(storeB, New ItemComparer())
For Each product In union
Console.WriteLine(product.Name & " " & product.Code)
Next
End Sub
End Class
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