C# 可选参数 (开发人员如何使用)

public static void DisplayGreeting(string message, string end = "!")
{
    Console.WriteLine(message + end);
}

Public Shared Sub DisplayGreeting(ByVal message As String, Optional ByVal [end] As String = "!")
	Console.WriteLine(message & [end])
End Sub

static void Main()
{
    DisplayGreeting("Hello"); // Outputs: Hello!
    DisplayGreeting("Hello", "?"); // Outputs: Hello?
}

Shared Sub Main()
	DisplayGreeting("Hello") ' Outputs: Hello!
	DisplayGreeting("Hello", "?") ' Outputs: Hello?
End Sub

// named parameters
public static void ConfigureDevice(string deviceName, bool enableLogging = false, int timeout = 30)
{
    Console.WriteLine($"Configuring {deviceName}: Logging={(enableLogging ? "On" : "Off")}, Timeout={timeout}s");
}

' named parameters
Public Shared Sub ConfigureDevice(ByVal deviceName As String, Optional ByVal enableLogging As Boolean = False, Optional ByVal timeout As Integer = 30)
	Console.WriteLine($"Configuring {deviceName}: Logging={(If(enableLogging, "On", "Off"))}, Timeout={timeout}s")
End Sub

static void Main()
{
    ConfigureDevice("Router", timeout: 60);
}

Shared Sub Main()
	ConfigureDevice("Router", timeout:= 60)
End Sub

public static void CreateProfile(string firstName, string lastName, int age = 25, string city = "Unknown")
{
    Console.WriteLine($"Name: {firstName} {lastName}, Age: {age}, City: {city}");
}

Public Shared Sub CreateProfile(ByVal firstName As String, ByVal lastName As String, Optional ByVal age As Integer = 25, Optional ByVal city As String = "Unknown")
	Console.WriteLine($"Name: {firstName} {lastName}, Age: {age}, City: {city}")
End Sub

static void Main()
{
    CreateProfile("John", "Doe"); // Uses default age and city
    CreateProfile("Jane", "Doe", 30, "New York"); // Specifies all parameters
}

Shared Sub Main()
	CreateProfile("John", "Doe") ' Uses default age and city
	CreateProfile("Jane", "Doe", 30, "New York") ' Specifies all parameters
End Sub

public static void SendEmail(string address, string subject = "No Subject", string body = "")
{
    Console.WriteLine($"Sending email to {address}\nSubject: {subject}\nBody: {body}");
}

Imports Microsoft.VisualBasic

Public Shared Sub SendEmail(ByVal address As String, Optional ByVal subject As String = "No Subject", Optional ByVal body As String = "")
	Console.WriteLine($"Sending email to {address}" & vbLf & "Subject: {subject}" & vbLf & "Body: {body}")
End Sub

// method overloading
public static void Alert(string message)
{
    Console.WriteLine(message);
}
public static void Alert(string message, bool urgent)
{
    if (urgent)
        Console.WriteLine("Urgent: " + message);
    else
        Console.WriteLine(message);
}

' method overloading
Public Shared Sub Alert(ByVal message As String)
	Console.WriteLine(message)
End Sub
Public Shared Sub Alert(ByVal message As String, ByVal urgent As Boolean)
	If urgent Then
		Console.WriteLine("Urgent: " & message)
	Else
		Console.WriteLine(message)
	End If
End Sub

public static void Alert(string message, bool urgent = false)
{
    if (urgent)
        Console.WriteLine("Urgent: " + message);
    else
        Console.WriteLine(message);
}

Public Shared Sub Alert(ByVal message As String, Optional ByVal urgent As Boolean = False)
	If urgent Then
		Console.WriteLine("Urgent: " & message)
	Else
		Console.WriteLine(message)
	End If
End Sub

using IronPdf;

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();

        // 1. Convert HTML String to PDF
        var htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>";
        var pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent);
        pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf");

        // 2. Convert HTML File to PDF
        var htmlFilePath = "path_to_your_html_file.html"; // Specify the path to your HTML file
        var pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath);
        pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf");

        // 3. Convert URL to PDF
        var url = "http://ironpdf.com"; // Specify the URL
        var pdfFromUrl = renderer.RenderUrlAsPdf(url);
        pdfFromUrl.SaveAs("URLToPDF.pdf");
    }
}

Imports IronPdf

Friend Class Program
	Shared Sub Main(ByVal args() As String)
		Dim renderer = New ChromePdfRenderer()

		' 1. Convert HTML String to PDF
		Dim htmlContent = "<h1>Hello, IronPDF!</h1><p>This is a PDF from an HTML string.</p>"
		Dim pdfFromHtmlString = renderer.RenderHtmlAsPdf(htmlContent)
		pdfFromHtmlString.SaveAs("HTMLStringToPDF.pdf")

		' 2. Convert HTML File to PDF
		Dim htmlFilePath = "path_to_your_html_file.html" ' Specify the path to your HTML file
		Dim pdfFromHtmlFile = renderer.RenderHtmlFileAsPdf(htmlFilePath)
		pdfFromHtmlFile.SaveAs("HTMLFileToPDF.pdf")

		' 3. Convert URL to PDF
		Dim url = "http://ironpdf.com" ' Specify the URL
		Dim pdfFromUrl = renderer.RenderUrlAsPdf(url)
		pdfFromUrl.SaveAs("URLToPDF.pdf")
	End Sub
End Class

using IronPdf;
using System;
public class PdfReportGenerator
{
    // Method to generate PDF with optional parameters
    public static void CreatePdfReport(string htmlContent, string filePath = "Report.pdf", bool includeCharts = true, string reportTitle = "Monthly Report")
    {
        // Optional parameters allow customization of the report's title and content dynamically
        var renderer = new ChromePdfRenderer();
        // Customize the PDF document
        renderer.RenderingOptions.TextHeader.CenterText = reportTitle;
        renderer.RenderingOptions.TextFooter.CenterText = "Generated on " + DateTime.Now.ToString("dd-MM-yyyy");
        renderer.RenderingOptions.MarginTop = 50;  // Set the top margin
        renderer.RenderingOptions.MarginBottom = 50;  // Set the bottom margin
        if (!includeCharts)
        {
            // Modify HTML content to remove chart sections if not included
            htmlContent = htmlContent.Replace("<div class='charts'></div>", "");
        }
        // Render the HTML to PDF
        PdfDocument pdf = renderer.RenderHtmlAsPdf(htmlContent);
        // Save the generated PDF to a file
        pdf.SaveAs(filePath);
        Console.WriteLine($"PDF report has been created at {filePath}");
    }
    static void Main()
    {
        License.LicenseKey = "License-Key";
        string htmlTemplate = @"
        <html>
        <head>
            <title>Monthly Report</title>
        </head>
        <body>
            <h1>Monthly Performance Report</h1>
            <p>This section contains text describing the overall performance for the month.</p>
            <div class='charts'>
                <h2>Sales Charts</h2>
                <!-- Placeholder for charts -->
            </div>
        </body>
        </html>";
        // Call the CreatePdfReport method with different parameters
        CreatePdfReport(htmlTemplate, "BasicReport.pdf", false, "Basic Monthly Report");
        CreatePdfReport(htmlTemplate, "FullReport.pdf", true, "Detailed Monthly Report");
    }
}

Imports IronPdf
Imports System
Public Class PdfReportGenerator
	' Method to generate PDF with optional parameters
	Public Shared Sub CreatePdfReport(ByVal htmlContent As String, Optional ByVal filePath As String = "Report.pdf", Optional ByVal includeCharts As Boolean = True, Optional ByVal reportTitle As String = "Monthly Report")
		' Optional parameters allow customization of the report's title and content dynamically
		Dim renderer = New ChromePdfRenderer()
		' Customize the PDF document
		renderer.RenderingOptions.TextHeader.CenterText = reportTitle
		renderer.RenderingOptions.TextFooter.CenterText = "Generated on " & DateTime.Now.ToString("dd-MM-yyyy")
		renderer.RenderingOptions.MarginTop = 50 ' Set the top margin
		renderer.RenderingOptions.MarginBottom = 50 ' Set the bottom margin
		If Not includeCharts Then
			' Modify HTML content to remove chart sections if not included
			htmlContent = htmlContent.Replace("<div class='charts'></div>", "")
		End If
		' Render the HTML to PDF
		Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf(htmlContent)
		' Save the generated PDF to a file
		pdf.SaveAs(filePath)
		Console.WriteLine($"PDF report has been created at {filePath}")
	End Sub
	Shared Sub Main()
		License.LicenseKey = "License-Key"
		Dim htmlTemplate As String = "
        <html>
        <head>
            <title>Monthly Report</title>
        </head>
        <body>
            <h1>Monthly Performance Report</h1>
            <p>This section contains text describing the overall performance for the month.</p>
            <div class='charts'>
                <h2>Sales Charts</h2>
                <!-- Placeholder for charts -->
            </div>
        </body>
        </html>"
		' Call the CreatePdfReport method with different parameters
		CreatePdfReport(htmlTemplate, "BasicReport.pdf", False, "Basic Monthly Report")
		CreatePdfReport(htmlTemplate, "FullReport.pdf", True, "Detailed Monthly Report")
	End Sub
End Class