C# Discriminated Union（開発者向けの仕組み）

// Method to handle the result using pattern matching.
public string HandleResult(OperationResult<int> result) =>
    result switch
    {
        OperationResult<int>.Success success => $"Operation succeeded with value: {success.Value}",
        OperationResult<int>.Failure failure => $"Operation failed with error: {failure.Error}",
        _ => throw new InvalidOperationException("Unexpected result type")
    };

' Method to handle the result using pattern matching.
'INSTANT VB TODO TASK: The following 'switch expression' was not converted by Instant VB:
'public string HandleResult(OperationResult<int> result) => result switch
'	{
'		OperationResult<int>.Success success => $"Operation succeeded with value: {success.Value}",
'		OperationResult<int>.Failure failure => $"Operation failed with error: {failure.Error}",
'		_ => throw new InvalidOperationException("Unexpected result type")
'	};

// Using directives for necessary namespaces.
using IronPdf;
using System;

// Define an abstract base class representing the PDF generation result.
public abstract class PdfResult
{
    // Private constructor to ensure the class cannot be instantiated directly.
    private PdfResult() { }

    // Nested class representing a successful PDF generation result.
    public sealed class Success : PdfResult
    {
        public PdfDocument Pdf { get; }

        public Success(PdfDocument pdf) => Pdf = pdf;

        public override string ToString() => "PDF generation succeeded";
    }

    // Nested class representing a failed PDF generation result.
    public sealed class Failure : PdfResult
    {
        public string ErrorMessage { get; }

        public Failure(string errorMessage) => ErrorMessage = errorMessage;

        public override string ToString() => $"PDF generation failed: {ErrorMessage}";
    }

    // Factory method to create a successful PDF result.
    public static PdfResult CreateSuccess(PdfDocument pdf) => new Success(pdf);

    // Factory method to create a failed PDF result.
    public static PdfResult CreateFailure(string errorMessage) => new Failure(errorMessage);
}

// Class to generate PDFs using IronPDF.
public class PdfGenerator
{
    // Method to generate a PDF from HTML content and return the result as a PdfResult.
    public PdfResult GeneratePdf(string htmlContent)
    {
        try
        {
            // Create a new ChromePdfRenderer instance.
            var renderer = new ChromePdfRenderer();

            // Attempt to render the HTML content as a PDF.
            var pdf = renderer.RenderHtmlAsPdf(htmlContent);

            // Return a success result with the generated PDF.
            return PdfResult.CreateSuccess(pdf);
        }
        catch (Exception ex)
        {
            // Return a failure result with the error message if an exception occurs.
            return PdfResult.CreateFailure(ex.Message);
        }
    }
}

' Using directives for necessary namespaces.
Imports IronPdf
Imports System

' Define an abstract base class representing the PDF generation result.
Public MustInherit Class PdfResult
	' Private constructor to ensure the class cannot be instantiated directly.
	Private Sub New()
	End Sub

	' Nested class representing a successful PDF generation result.
	Public NotInheritable Class Success
		Inherits PdfResult

		Public ReadOnly Property Pdf() As PdfDocument

		Public Sub New(ByVal pdf As PdfDocument)
			Me.Pdf = pdf
		End Sub

		Public Overrides Function ToString() As String
			Return "PDF generation succeeded"
		End Function
	End Class

	' Nested class representing a failed PDF generation result.
	Public NotInheritable Class Failure
		Inherits PdfResult

		Public ReadOnly Property ErrorMessage() As String

		Public Sub New(ByVal errorMessage As String)
			Me.ErrorMessage = errorMessage
		End Sub

		Public Overrides Function ToString() As String
			Return $"PDF generation failed: {ErrorMessage}"
		End Function
	End Class

	' Factory method to create a successful PDF result.
	Public Shared Function CreateSuccess(ByVal pdf As PdfDocument) As PdfResult
		Return New Success(pdf)
	End Function

	' Factory method to create a failed PDF result.
	Public Shared Function CreateFailure(ByVal errorMessage As String) As PdfResult
		Return New Failure(errorMessage)
	End Function
End Class

' Class to generate PDFs using IronPDF.
Public Class PdfGenerator
	' Method to generate a PDF from HTML content and return the result as a PdfResult.
	Public Function GeneratePdf(ByVal htmlContent As String) As PdfResult
		Try
			' Create a new ChromePdfRenderer instance.
			Dim renderer = New ChromePdfRenderer()

			' Attempt to render the HTML content as a PDF.
			Dim pdf = renderer.RenderHtmlAsPdf(htmlContent)

			' Return a success result with the generated PDF.
			Return PdfResult.CreateSuccess(pdf)
		Catch ex As Exception
			' Return a failure result with the error message if an exception occurs.
			Return PdfResult.CreateFailure(ex.Message)
		End Try
	End Function
End Class