Jak używać Fluent Validation z IronPDF w C#

Zrozumienie płynnej walidacji

Fluent Validation to biblioteka open source dla platformy .NET, która ułatwia tworzenie reguł walidacji dla klas modeli.

1. Walidatory: Walidatory to klasy, które hermetyzują logikę walidacji. They are typically created by inheriting from the AbstractValidator<t> base class.
2. Reguły: Reguła to warunek walidacji, który musi spełniać dana właściwość. Rules are defined using the RuleFor method in a validator class.
3. Validation Failures: If a rule fails, Fluent Validation creates a ValidationFailure object that contains details about the error, including the property name and error message.

Konfiguracja projektu

Na początek utwórzmy nową aplikację konsolową w Visual Studio lub innym preferowanym środowisku programistycznym.

1. Otwórz Visual Studio i przejdź do Plik > Nowy > Projekt.

2. Wybierz "Aplikacja konsolowa (ASP.NET Core)" jako szablon projektu i nadaj nazwę swojemu projektowi.

   Utwórz nową aplikację konsolową

3. Kliknij przycisk Dalej i skonfiguruj projekt, nadając mu nazwę oraz wybierając lokalizację repozytorium.

   Skonfiguruj nową aplikację

4. Kliknij przycisk Dalej i wybierz .NET Framework. Zalecane jest użycie najnowszej wersji .NET Framework (7).

   Wybór platformy .NET Framework

5. Kliknij przycisk Utwórz, aby utworzyć projekt.

Zainstaluj wymagane pakiety

Po utworzeniu projektu dodaj niezbędne pakiety NuGet dla Fluent Validation i IronPDF.

1. Kliknij prawym przyciskiem myszy projekt w Eksploratorze rozwiązań i wybierz opcję "Zarządzaj pakietami NuGet".

2. Wyszukaj "FluentValidation" i kliknij "Zainstaluj", aby dodać pakiet do swojego projektu.

   Zainstaluj pakiet FluentValidation w interfejsie użytkownika menedżera pakietów NuGet

3. Podobnie, wyszukaj "IronPDF – Potężna biblioteka PDF dla .NET" i zainstaluj pakiet IronPDF.

Alternatywnie można zainstalować IronPDF za pomocą konsoli NuGet Package Manager Console, używając następującego polecenia:

Install-Package IronPdf

Zainstaluj pakiet IronPdf w konsoli menedżera pakietów

Po skonfigurowaniu projektu i zainstalowaniu wymaganych pakietów przejdźmy do zdefiniowania klasy treści PDF.

Określenie treści pliku PDF

In this example, a simple invoice PDF will be created from the HTML codes in two classes: InvoiceContent and InvoiceItem.

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

public abstract class PdfContent
{
    // Abstract method to generate the HTML string
    public abstract string RenderHtml();
}

public class InvoiceContent : PdfContent
{
    public string CustomerName { get; set; }
    public string Address { get; set; }
    public List<InvoiceItem> InvoiceItems { get; set; }

    // Constructs the HTML representation of the invoice
    public override string RenderHtml()
    {
        string invoiceItemsHtml = string.Join("", InvoiceItems.Select(item => $"<li>{item.Description}: {item.Price}</li>"));
        return $"<h1>Invoice for {CustomerName}</h1><p>{Address}</p><ul>{invoiceItemsHtml}</ul>";
    }
}

public class InvoiceItem
{
    public string Description { get; set; }
    public decimal Price { get; set; }
}

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

public abstract class PdfContent
{
    // Abstract method to generate the HTML string
    public abstract string RenderHtml();
}

public class InvoiceContent : PdfContent
{
    public string CustomerName { get; set; }
    public string Address { get; set; }
    public List<InvoiceItem> InvoiceItems { get; set; }

    // Constructs the HTML representation of the invoice
    public override string RenderHtml()
    {
        string invoiceItemsHtml = string.Join("", InvoiceItems.Select(item => $"<li>{item.Description}: {item.Price}</li>"));
        return $"<h1>Invoice for {CustomerName}</h1><p>{Address}</p><ul>{invoiceItemsHtml}</ul>";
    }
}

public class InvoiceItem
{
    public string Description { get; set; }
    public decimal Price { get; set; }
}

Imports System.Collections.Generic
Imports System.Linq

Public MustInherit Class PdfContent
	' Abstract method to generate the HTML string
	Public MustOverride Function RenderHtml() As String
End Class

Public Class InvoiceContent
	Inherits PdfContent

	Public Property CustomerName() As String
	Public Property Address() As String
	Public Property InvoiceItems() As List(Of InvoiceItem)

	' Constructs the HTML representation of the invoice
	Public Overrides Function RenderHtml() As String
		Dim invoiceItemsHtml As String = String.Join("", InvoiceItems.Select(Function(item) $"<li>{item.Description}: {item.Price}</li>"))
		Return $"<h1>Invoice for {CustomerName}</h1><p>{Address}</p><ul>{invoiceItemsHtml}</ul>"
	End Function
End Class

Public Class InvoiceItem
	Public Property Description() As String
	Public Property Price() As Decimal
End Class

In the code above, an abstract PdfContent class is defined with an abstract method called RenderHtml. The InvoiceContent class extends PdfContent and represents the content of the invoice PDF. Zawiera pola dotyczące nazwy klienta, adresu oraz listy pozycji na fakturze. The InvoiceItem class contains two properties: 'Description' and 'Price'. The RenderHtml method generates the HTML markup for the invoice based on the content.

Teraz, gdy zawartość pliku PDF została zdefiniowana, przejdźmy do tworzenia reguł walidacji przy użyciu Fluent Validation.

Tworzenie reguł walidacji

For building validation rules for the InvoiceContent class, create a validator class called InvoiceContentValidator. This class will inherit from AbstractValidator<InvoiceContent>, which is provided by FluentValidation.

using FluentValidation;

public class InvoiceContentValidator : AbstractValidator<InvoiceContent>
{
    public InvoiceContentValidator()
    {
        RuleFor(content => content.CustomerName).NotEmpty().WithMessage("Customer name is required.");
        RuleFor(content => content.Address).NotEmpty().WithMessage("Address is required.");
        RuleFor(content => content.InvoiceItems).NotEmpty().WithMessage("At least one invoice item is required.");
        RuleForEach(content => content.InvoiceItems).SetValidator(new InvoiceItemValidator());
    }
}

public class InvoiceItemValidator : AbstractValidator<InvoiceItem>
{
    public InvoiceItemValidator()
    {
        RuleFor(item => item.Description).NotEmpty().WithMessage("Description is required.");
        RuleFor(item => item.Price).GreaterThanOrEqualTo(0).WithMessage("Price must be greater than or equal to 0.");
    }
}

using FluentValidation;

public class InvoiceContentValidator : AbstractValidator<InvoiceContent>
{
    public InvoiceContentValidator()
    {
        RuleFor(content => content.CustomerName).NotEmpty().WithMessage("Customer name is required.");
        RuleFor(content => content.Address).NotEmpty().WithMessage("Address is required.");
        RuleFor(content => content.InvoiceItems).NotEmpty().WithMessage("At least one invoice item is required.");
        RuleForEach(content => content.InvoiceItems).SetValidator(new InvoiceItemValidator());
    }
}

public class InvoiceItemValidator : AbstractValidator<InvoiceItem>
{
    public InvoiceItemValidator()
    {
        RuleFor(item => item.Description).NotEmpty().WithMessage("Description is required.");
        RuleFor(item => item.Price).GreaterThanOrEqualTo(0).WithMessage("Price must be greater than or equal to 0.");
    }
}

Imports FluentValidation

Public Class InvoiceContentValidator
	Inherits AbstractValidator(Of InvoiceContent)

	Public Sub New()
		RuleFor(Function(content) content.CustomerName).NotEmpty().WithMessage("Customer name is required.")
		RuleFor(Function(content) content.Address).NotEmpty().WithMessage("Address is required.")
		RuleFor(Function(content) content.InvoiceItems).NotEmpty().WithMessage("At least one invoice item is required.")
		RuleForEach(Function(content) content.InvoiceItems).SetValidator(New InvoiceItemValidator())
	End Sub
End Class

Public Class InvoiceItemValidator
	Inherits AbstractValidator(Of InvoiceItem)

	Public Sub New()
		RuleFor(Function(item) item.Description).NotEmpty().WithMessage("Description is required.")
		RuleFor(Function(item) item.Price).GreaterThanOrEqualTo(0).WithMessage("Price must be greater than or equal to 0.")
	End Sub
End Class

In the source code, the InvoiceContentValidator class is defined, which inherits from AbstractValidator<InvoiceContent>. Inside the constructor of the validator class, the RuleFor method defines validation rules for each property of the InvoiceContent class.

For example, RuleFor(content => content.CustomerName) specifies that the customer name should not be empty. Podobnie zdefiniowano reguły walidacji dla właściwości pozycji adresu i faktury.

The RuleForEach method iterates over each item in the InvoiceItems list and applies the InvoiceItemValidator. The InvoiceItemValidator class contains validation rules for the InvoiceItem class.

Mając te zasady walidacji, przejdźmy do generowania pliku PDF przy użyciu IronPDF.

Generowanie plików PDF za pomocą IronPDF

IronPDF – Generowanie i edycja dokumentów PDF to popularna biblioteka .NET służąca do tworzenia i edycji dokumentów PDF. Do wygenerowania pliku PDF na podstawie zweryfikowanej treści faktury zostanie użyty IronPDF.

using IronPdf;
using FluentValidation;

public class PdfService
{
    // Generates a PDF document for the provided content
    public PdfDocument GeneratePdf<t>(T content) where T : PdfContent
    {
        // Validate the content using the appropriate validator
        var validator = GetValidatorForContent(content);
        var validationResult = validator.Validate(content);

        // Check if validation is successful
        if (!validationResult.IsValid)
        {
            throw new FluentValidation.ValidationException(validationResult.Errors);
        }

        // Generate the PDF using IronPDF
        var renderer = new ChromePdfRenderer();
        return renderer.RenderHtmlAsPdf(content.RenderHtml());
    }

    // Retrieves the appropriate validator for the content
    private IValidator<t> GetValidatorForContent<t>(T content) where T : PdfContent
    {
        if (content is InvoiceContent)
        {
            return (IValidator<t>)new InvoiceContentValidator();
        }
        else
        {
            throw new NotSupportedException("Unsupported content type.");
        }
    }
}

using IronPdf;
using FluentValidation;

public class PdfService
{
    // Generates a PDF document for the provided content
    public PdfDocument GeneratePdf<t>(T content) where T : PdfContent
    {
        // Validate the content using the appropriate validator
        var validator = GetValidatorForContent(content);
        var validationResult = validator.Validate(content);

        // Check if validation is successful
        if (!validationResult.IsValid)
        {
            throw new FluentValidation.ValidationException(validationResult.Errors);
        }

        // Generate the PDF using IronPDF
        var renderer = new ChromePdfRenderer();
        return renderer.RenderHtmlAsPdf(content.RenderHtml());
    }

    // Retrieves the appropriate validator for the content
    private IValidator<t> GetValidatorForContent<t>(T content) where T : PdfContent
    {
        if (content is InvoiceContent)
        {
            return (IValidator<t>)new InvoiceContentValidator();
        }
        else
        {
            throw new NotSupportedException("Unsupported content type.");
        }
    }
}

Imports IronPdf
Imports FluentValidation

Public Class PdfService
    ' Generates a PDF document for the provided content
    Public Function GeneratePdf(Of T As PdfContent)(content As T) As PdfDocument
        ' Validate the content using the appropriate validator
        Dim validator = GetValidatorForContent(content)
        Dim validationResult = validator.Validate(content)

        ' Check if validation is successful
        If Not validationResult.IsValid Then
            Throw New FluentValidation.ValidationException(validationResult.Errors)
        End If

        ' Generate the PDF using IronPDF
        Dim renderer = New ChromePdfRenderer()
        Return renderer.RenderHtmlAsPdf(content.RenderHtml())
    End Function

    ' Retrieves the appropriate validator for the content
    Private Function GetValidatorForContent(Of T As PdfContent)(content As T) As IValidator(Of T)
        If TypeOf content Is InvoiceContent Then
            Return CType(New InvoiceContentValidator(), IValidator(Of T))
        Else
            Throw New NotSupportedException("Unsupported content type.")
        End If
    End Function
End Class

The PdfService class provides a GeneratePdf method. This method takes a PdfContent object as input and generates the PDF document based on the validated content.

First, it retrieves the appropriate validator for the content by calling the GetValidatorForContent method, which checks the type of content and returns the corresponding validator. In our case, we support InvoiceContent and use the InvoiceContentValidator.

Next, the content is validated using the validator by calling its Validate method. The validation result is stored in a ValidationResult object.

If the validation fails (!validationResult.IsValid), a FluentValidation.ValidationException is thrown with the validation errors. Otherwise, the PDF is generated using IronPDF.

An instance of ChromePdfRenderer is created to render the HTML content as a PDF. The RenderHtmlAsPdf method is called on the renderer object, passing in the HTML generated by the content.RenderHtml method, generating the PDF document.

Now that we have defined the PDF generation logic, let's handle any validation errors that may occur.

Handling Validation Errors

When a validation error occurs, we want to display an error message and handle it gracefully. Let's modify the Main method of the Program class to handle any exceptions and display meaningful messages to the user.

using System;
using System.Collections.Generic;

public class Program
{
    static void Main(string[] args)
    {
        var pdfService = new PdfService();

        // Test 1: Empty Customer Name
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem> {
                    new InvoiceItem { Description = "Item 1", Price = 19.99M },
                    new InvoiceItem { Description = "Item 2", Price = 29.99M }
                }
            };

            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }

        // Test 2: Empty InvoiceItems
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "John Doe",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem>()  // Empty list
            };

            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }

        // Successful generation
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "John Doe",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem> {
                    new InvoiceItem { Description = "Item 1", Price = 19.99M },
                    new InvoiceItem { Description = "Item 2", Price = 29.99M }
                }
            };
            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }
    }
}

using System;
using System.Collections.Generic;

public class Program
{
    static void Main(string[] args)
    {
        var pdfService = new PdfService();

        // Test 1: Empty Customer Name
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem> {
                    new InvoiceItem { Description = "Item 1", Price = 19.99M },
                    new InvoiceItem { Description = "Item 2", Price = 29.99M }
                }
            };

            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }

        // Test 2: Empty InvoiceItems
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "John Doe",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem>()  // Empty list
            };

            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }

        // Successful generation
        try
        {
            var invoiceContent = new InvoiceContent
            {
                CustomerName = "John Doe",
                Address = "123 Main St, Anytown, USA",
                InvoiceItems = new List<InvoiceItem> {
                    new InvoiceItem { Description = "Item 1", Price = 19.99M },
                    new InvoiceItem { Description = "Item 2", Price = 29.99M }
                }
            };
            var pdfDocument = pdfService.GeneratePdf(invoiceContent);
            pdfDocument.SaveAs("C:\\TestInvoice.pdf");
            Console.WriteLine("PDF generated successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error generating PDF: " + ex.Message);
        }
    }
}

Imports System
Imports System.Collections.Generic

Public Class Program
	Shared Sub Main(ByVal args() As String)
		Dim pdfService As New PdfService()

		' Test 1: Empty Customer Name
		Try
			Dim invoiceContent As New InvoiceContent With {
				.CustomerName = "",
				.Address = "123 Main St, Anytown, USA",
				.InvoiceItems = New List(Of InvoiceItem) From {
					New InvoiceItem With {
						.Description = "Item 1",
						.Price = 19.99D
					},
					New InvoiceItem With {
						.Description = "Item 2",
						.Price = 29.99D
					}
				}
			}

			Dim pdfDocument = pdfService.GeneratePdf(invoiceContent)
			pdfDocument.SaveAs("C:\TestInvoice.pdf")
			Console.WriteLine("PDF generated successfully!")
		Catch ex As Exception
			Console.WriteLine("Error generating PDF: " & ex.Message)
		End Try

		' Test 2: Empty InvoiceItems
		Try
			Dim invoiceContent As New InvoiceContent With {
				.CustomerName = "John Doe",
				.Address = "123 Main St, Anytown, USA",
				.InvoiceItems = New List(Of InvoiceItem)()
			}

			Dim pdfDocument = pdfService.GeneratePdf(invoiceContent)
			pdfDocument.SaveAs("C:\TestInvoice.pdf")
			Console.WriteLine("PDF generated successfully!")
		Catch ex As Exception
			Console.WriteLine("Error generating PDF: " & ex.Message)
		End Try

		' Successful generation
		Try
			Dim invoiceContent As New InvoiceContent With {
				.CustomerName = "John Doe",
				.Address = "123 Main St, Anytown, USA",
				.InvoiceItems = New List(Of InvoiceItem) From {
					New InvoiceItem With {
						.Description = "Item 1",
						.Price = 19.99D
					},
					New InvoiceItem With {
						.Description = "Item 2",
						.Price = 29.99D
					}
				}
			}
			Dim pdfDocument = pdfService.GeneratePdf(invoiceContent)
			pdfDocument.SaveAs("C:\TestInvoice.pdf")
			Console.WriteLine("PDF generated successfully!")
		Catch ex As Exception
			Console.WriteLine("Error generating PDF: " & ex.Message)
		End Try
	End Sub
End Class

In the code above, try-catch blocks are used to catch any exceptions that may occur. If an exception is caught, an error message will be shown to the user using Console.WriteLine.

Now let's test this application with different scenarios to validate the PDF generation and the validation rules.

Testowanie aplikacji

In the code example, there are three scenarios to test:

1. Empty customer name: Leave the customer name empty to trigger a validation error.
2. Empty invoice items: Provide an empty list of invoice items to trigger a validation error.
3. Successful generation: Provide valid content to generate the PDF successfully.

Run the application and observe the output in the console.

Error generating PDF: Validation failed:
    -- CustomerName: Customer name is required. Severity: Error
Error generating PDF: Validation failed:
    -- InvoiceItems: At least one invoice item is required. Severity: Error
PDF generated successfully!

The output error in the Console

Plik PDF wynikowy

As expected, validation errors are shown for the first two scenarios and a success message for the third scenario.