C# インデクサー（開発者のための仕組み）

public return_type this[parameter_type index]
{
    get
    {
        // code to return data
    }
    set
    {
        // set accessor, code to set data
    }
}

Default Public Property Item(ByVal index As parameter_type) As return_type
	Get
		' code to return data
	End Get
	Set(ByVal value As return_type)
		' set accessor, code to set data
	End Set
End Property

class Program
{
    private string[] values = new string[5]; // Array with 5 elements
    public string this[int index]
    {
        get
        {
            return values[index];
        }
        set
        {
            values[index] = value;
        }
    }
}

Friend Class Program
	Private values(4) As String ' Array with 5 elements
	Default Public Property Item(ByVal index As Integer) As String
		Get
			Return values(index)
		End Get
		Set(ByVal value As String)
			values(index) = value
		End Set
	End Property
End Class

class Program
{
    static void Main()
    {
        Program program = new Program();
        // Set values using indexer
        program[0] = "First";
        program[1] = "Second";
        // Access values using indexer
        Console.WriteLine(program[0]); // Output: First
        Console.WriteLine(program[1]); // Output: Second
    }
}

Friend Class Program
	Shared Sub Main()
		Dim program As New Program()
		' Set values using indexer
		program(0) = "First"
		program(1) = "Second"
		' Access values using indexer
		Console.WriteLine(program(0)) ' Output: First
		Console.WriteLine(program(1)) ' Output: Second
	End Sub
End Class

class StudentRecords
{
    private string[] studentNames = new string[3];
    public string this[int index]
    {
        get
        {
            if (index >= 0 && index < studentNames.Length)
            {
                return studentNames[index];
            }
            return "Invalid Index";
        }
        set
        {
            if (index >= 0 && index < studentNames.Length)
            {
                studentNames[index] = value;
            }
        }
    }
    public int Length
    {
        get { return studentNames.Length; }
    }
}

Friend Class StudentRecords
	Private studentNames(2) As String
	Default Public Property Item(ByVal index As Integer) As String
		Get
			If index >= 0 AndAlso index < studentNames.Length Then
				Return studentNames(index)
			End If
			Return "Invalid Index"
		End Get
		Set(ByVal value As String)
			If index >= 0 AndAlso index < studentNames.Length Then
				studentNames(index) = value
			End If
		End Set
	End Property
	Public ReadOnly Property Length() As Integer
		Get
			Return studentNames.Length
		End Get
	End Property
End Class

class Program
{
    public static void Main()
    {
        StudentRecords records = new StudentRecords();
        // Set values using indexer
        records[0] = "John";
        records[1] = "Jane";
        records[2] = "Bob";
        // Access values using indexer
        for (int i = 0; i < records.Length; i++)
        {
            Console.WriteLine(records[i]);
        }
    }
}

Friend Class Program
	Public Shared Sub Main()
		Dim records As New StudentRecords()
		' Set values using indexer
		records(0) = "John"
		records(1) = "Jane"
		records(2) = "Bob"
		' Access values using indexer
		For i As Integer = 0 To records.Length - 1
			Console.WriteLine(records(i))
		Next i
	End Sub
End Class

class GenericClass<T>
{
    private T[] elements = new T[5];
    public T this[int index]
    {
        get
        {
            return elements[index];
        }
        set
        {
            elements[index] = value;
        }
    }
    public int Length
    {
        get { return elements.Length; }
    }
}

Friend Class GenericClass(Of T)
	Private elements(4) As T
	Default Public Property Item(ByVal index As Integer) As T
		Get
			Return elements(index)
		End Get
		Set(ByVal value As T)
			elements(index) = value
		End Set
	End Property
	Public ReadOnly Property Length() As Integer
		Get
			Return elements.Length
		End Get
	End Property
End Class

class Program
{
    public static void Main()
    {
        GenericClass<int> intArray = new GenericClass<int>();
        intArray[0] = 10;
        intArray[1] = 20;
        GenericClass<string> stringArray = new GenericClass<string>();
        stringArray[0] = "Hello";
        stringArray[1] = "World";
        // Output the integer array values
        for (int i = 0; i < intArray.Length; i++)
        {
            Console.WriteLine(intArray[i]);
        }
        // Output the string array values
        for (int i = 0; i < stringArray.Length; i++)
        {
            Console.WriteLine(stringArray[i]);
        }
    }
}

Friend Class Program
	Public Shared Sub Main()
		Dim intArray As New GenericClass(Of Integer)()
		intArray(0) = 10
		intArray(1) = 20
		Dim stringArray As New GenericClass(Of String)()
		stringArray(0) = "Hello"
		stringArray(1) = "World"
		' Output the integer array values
		For i As Integer = 0 To intArray.Length - 1
			Console.WriteLine(intArray(i))
		Next i
		' Output the string array values
		For i As Integer = 0 To stringArray.Length - 1
			Console.WriteLine(stringArray(i))
		Next i
	End Sub
End Class

using IronPdf;
using System;
class PdfGenerator
{
    private string[] htmlTemplates = new string[3];
    public string this[int index]
    {
        get { return htmlTemplates[index]; }
        set { htmlTemplates[index] = value; }
    }
    public void GeneratePdf(int index, string outputPath)
    {
        var renderer = new ChromePdfRenderer();
        var pdfDocument = renderer.RenderHtmlAsPdf(this[index]); // Access HTML string using indexer
        pdfDocument.SaveAs(outputPath);
    }
}
class Program
{
    public static void Main()
    {
        PdfGenerator pdfGen = new PdfGenerator();
        // Populate HTML templates
        pdfGen[0] = "<h1>First Document</h1><p>This is the first PDF.</p>";
        pdfGen[1] = "<h1>Second Document</h1><p>This is the second PDF.</p>";
        pdfGen[2] = "<h1>Third Document</h1><p>This is the third PDF.</p>";
        // Generate PDFs using the indexer
        pdfGen.GeneratePdf(0, "first.pdf");
        pdfGen.GeneratePdf(1, "second.pdf");
        pdfGen.GeneratePdf(2, "third.pdf");
        Console.WriteLine("PDFs generated successfully.");
    }
}

Imports IronPdf
Imports System
Friend Class PdfGenerator
	Private htmlTemplates(2) As String
	Default Public Property Item(ByVal index As Integer) As String
		Get
			Return htmlTemplates(index)
		End Get
		Set(ByVal value As String)
			htmlTemplates(index) = value
		End Set
	End Property
	Public Sub GeneratePdf(ByVal index As Integer, ByVal outputPath As String)
		Dim renderer = New ChromePdfRenderer()
		Dim pdfDocument = renderer.RenderHtmlAsPdf(Me(index)) ' Access HTML string using indexer
		pdfDocument.SaveAs(outputPath)
	End Sub
End Class
Friend Class Program
	Public Shared Sub Main()
		Dim pdfGen As New PdfGenerator()
		' Populate HTML templates
		pdfGen(0) = "<h1>First Document</h1><p>This is the first PDF.</p>"
		pdfGen(1) = "<h1>Second Document</h1><p>This is the second PDF.</p>"
		pdfGen(2) = "<h1>Third Document</h1><p>This is the third PDF.</p>"
		' Generate PDFs using the indexer
		pdfGen.GeneratePdf(0, "first.pdf")
		pdfGen.GeneratePdf(1, "second.pdf")
		pdfGen.GeneratePdf(2, "third.pdf")
		Console.WriteLine("PDFs generated successfully.")
	End Sub
End Class