Imports System
Imports System.Collections.Generic
Imports System.Linq
Namespace ListReturnExample
''' <summary>
''' Represents a product in the system.
''' </summary>
Public Class Product
''' <summary>
''' Gets or sets the product name.
''' </summary>
Public Property Name As String
''' <summary>
''' Gets or sets the product price.
''' </summary>
Public Property Price As Decimal
End Class
''' <summary>
''' Provides product-related business operations.
''' </summary>
Public Class ProductService
''' <summary>
''' Returns all products having a price greater than or equal to the specified minimum price.
''' </summary>
''' <param name="minimumPrice">
''' The minimum price required for a product to be included.
''' </param>
''' <returns>
''' A list of matching products.
''' </returns>
''' <exception cref="ArgumentOutOfRangeException">
''' Thrown when minimumPrice is less than zero.
''' </exception>
Public Function GetProductsByMinimumPrice(minimumPrice As Decimal) As List(Of Product)
If minimumPrice < 0 Then
Throw New ArgumentOutOfRangeException(
NameOf(minimumPrice),
"Minimum price cannot be negative.")
End If
' Sample data.
Dim products As New List(Of Product) From {
New Product With {.Name = "Laptop", .Price = 1200D},
New Product With {.Name = "Mouse", .Price = 25D},
New Product With {.Name = "Keyboard", .Price = 80D},
New Product With {.Name = "Monitor", .Price = 300D}
}
' Filter and return matching products.
Return products.
Where(Function(p) p.Price >= minimumPrice).
ToList()
End Function
End Class
Module Program
Sub Main()
Try
Dim productService As New ProductService()
' Call the public function that returns a List(Of Product).
Dim filteredProducts As List(Of Product) =
productService.GetProductsByMinimumPrice(100D)
For Each product As Product In filteredProducts
Console.WriteLine($"{product.Name} - ${product.Price}")
Next
Catch ex As Exception
Console.WriteLine($"Error: {ex.Message}")
End Try
End Sub
End Module
End Namespace
'
' run:
'
' Laptop - $1200
' Monitor - $300
'
