C# Params（對於開發者的運行原理）

class Program
{
    public static void Main()
    {
        var items = new string[] { "cold drink", "snack", "roll" }; // 1D string array
        AddItemsToShoppingBasket(items); // Works as expected
        AddItemsToShoppingBasket("cold drink", "coke", "roll"); // Similar result to the above line
    }
}

Friend Class Program
	Public Shared Sub Main()
		Dim items = New String() { "cold drink", "snack", "roll" } ' 1D string array
		AddItemsToShoppingBasket(items) ' Works as expected
		AddItemsToShoppingBasket("cold drink", "coke", "roll") ' Similar result to the above line
	End Sub
End Class

class Program
{
    public static void Main()
    {
        // Example method signature
        AddItemsToShoppingBasket("snacks", "burger", "snacks", "burger", "cold drink"); // Comma separated values
        AddItemsToShoppingBasket("snacks");
    }
}

Friend Class Program
	Public Shared Sub Main()
		' Example method signature
		AddItemsToShoppingBasket("snacks", "burger", "snacks", "burger", "cold drink") ' Comma separated values
		AddItemsToShoppingBasket("snacks")
	End Sub
End Class

// Example that results in an error
AddItemsToShoppingBasket("snacks", 2, "burger"); // Error due to type mismatch
AddItemsToShoppingBasket(2, 3, 4); // Error since params type is string

' Example that results in an error
AddItemsToShoppingBasket("snacks", 2, "burger") ' Error due to type mismatch
AddItemsToShoppingBasket(2, 3, 4) ' Error since params type is string

class Program
{
    static void Main(string[] args)
    {
        // Example 1
        public static void AddItemsToShoppingBasket(double total, params string[] items)
        {
            // Works fine as `params` is the last parameter
        }

        // Example 2, error scenario
        public static void AddItemsToShoppingBasket(params string[] items, decimal total, int total)
        {
            // Error: `params` keyword must be the last parameter 
        }
    }
}

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		' Example 1
'INSTANT VB TODO TASK: Local functions are not converted by Instant VB:
'		public static void AddItemsToShoppingBasket(double total, params string[] items)
'		{
'			' Works fine as `params` is the last parameter
'		}

		' Example 2, error scenario
'INSTANT VB TODO TASK: Local functions are not converted by Instant VB:
'		public static void AddItemsToShoppingBasket(params string[] items, decimal total, int total)
'		{
'			' Error: `params` keyword must be the last parameter 
'		}
	End Sub
End Class

class Program
{
    static void Main(string[] args)
    {
        public static void AddItemsToShoppingBasket(params string[] items, params string[] quantity)
        {
            // Compiler Error: Only one params keyword is allowed in the method signature
        }
    }
}

Friend Class Program
	Shared Sub Main(ByVal args() As String)
'INSTANT VB TODO TASK: Local functions are not converted by Instant VB:
'		public static void AddItemsToShoppingBasket(params string[] items, params string[] quantity)
'		{
'			' Compiler Error: Only one params keyword is allowed in the method signature
'		}
	End Sub
End Class

AddItemsToShoppingBasket(); // Works as expected

AddItemsToShoppingBasket() ' Works as expected

using System;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        List<string> cart = new List<string>();

        void AddItemsToShoppingBasket(params string[] samples)
        {
            for (int i = 0; i < samples.Length; i++)
            {
                cart.Add(samples[i]);
            }
        }

        // Caller code
        Console.WriteLine("Enter the cart items as comma separated values");
        var itemsString = Console.ReadLine();
        if (itemsString != null)
        {
            var items = itemsString.Split(",").ToArray();
            AddItemsToShoppingBasket(items);
        }
        AddItemsToShoppingBasket("Sample1", "Sample2");

        Console.WriteLine("-------------------------------------------------------");
        Console.WriteLine("Display Cart");

        foreach (var item in cart)
        {
            Console.WriteLine(item);
        }
    }
}

Imports System
Imports System.Collections.Generic

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim cart As New List(Of String)()

'INSTANT VB TODO TASK: Local functions are not converted by Instant VB:
'		void AddItemsToShoppingBasket(params string[] samples)
'		{
'			for (int i = 0; i < samples.Length; i++)
'			{
'				cart.Add(samples[i]);
'			}
'		}

		' Caller code
		Console.WriteLine("Enter the cart items as comma separated values")
		Dim itemsString = Console.ReadLine()
		If itemsString IsNot Nothing Then
			Dim items = itemsString.Split(",").ToArray()
			AddItemsToShoppingBasket(items)
		End If
		AddItemsToShoppingBasket("Sample1", "Sample2")

		Console.WriteLine("-------------------------------------------------------")
		Console.WriteLine("Display Cart")

		For Each item In cart
			Console.WriteLine(item)
		Next item
	End Sub
End Class

using System;
using System.Collections.Generic;
using System.Linq;
using IronPdf;

class Program
{
    public static void Main()
    {
        List<string> cart = new List<string>();

        void AddItemsToShoppingBasket(params string[] items)
        {
            for (int i = 0; i < items.Length; i++)
            {
                cart.Add(items[i]);
            }
        }

        // Take input from console
        Console.WriteLine("Enter the cart items as comma separated values");
        var itemsString = Console.ReadLine();

        // Read the items
        if (itemsString != null)
        {
            var items = itemsString.Split(",").ToArray();
            AddItemsToShoppingBasket(items);
        }

        // Add to cart
        AddItemsToShoppingBasket("Sample1", "Sample2");

        Console.WriteLine("------------------------------------------------");
        Console.WriteLine("Display Cart");
        Console.WriteLine("------------------------------------------------");

        string name = "Sam";
        var count = cart.Count;
        string content = $@"<!DOCTYPE html>
<html>
<body>
<h1>Hello, {name}!</h1>
<p>You have {count} items in the cart.</p>
" +
        string.Join("\n", cart.Select(x => $"<p>{x}</p>"))
        + @"
</body>
</html>";

        // Create a new PDF document
        var pdfDoc = new ChromePdfRenderer();
        pdfDoc.RenderHtmlAsPdf(content).SaveAs("cart.pdf");
    }
}

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports IronPdf

Friend Class Program
	Public Shared Sub Main()
		Dim cart As New List(Of String)()

'INSTANT VB TODO TASK: Local functions are not converted by Instant VB:
'		void AddItemsToShoppingBasket(params string[] items)
'		{
'			for (int i = 0; i < items.Length; i++)
'			{
'				cart.Add(items[i]);
'			}
'		}

		' Take input from console
		Console.WriteLine("Enter the cart items as comma separated values")
		Dim itemsString = Console.ReadLine()

		' Read the items
		If itemsString IsNot Nothing Then
			Dim items = itemsString.Split(",").ToArray()
			AddItemsToShoppingBasket(items)
		End If

		' Add to cart
		AddItemsToShoppingBasket("Sample1", "Sample2")

		Console.WriteLine("------------------------------------------------")
		Console.WriteLine("Display Cart")
		Console.WriteLine("------------------------------------------------")

		Dim name As String = "Sam"
		Dim count = cart.Count
		Dim content As String = $"<!DOCTYPE html>
<html>
<body>
<h1>Hello, {name}!</h1>
<p>You have {count} items in the cart.</p>
" & String.Join(vbLf, cart.Select(Function(x) $"<p>{x}</p>")) & "
</body>
</html>"

		' Create a new PDF document
		Dim pdfDoc = New ChromePdfRenderer()
		pdfDoc.RenderHtmlAsPdf(content).SaveAs("cart.pdf")
	End Sub
End Class