C# 常量（开发人员如何使用）

public class Program
{
    public const int MaxSize = 10;
    static void Main(string [] args)
    {
        Console.WriteLine(MaxSize);
    }
}

Public Class Program
	Public Const MaxSize As Integer = 10
	Shared Sub Main(ByVal args() As String)
		Console.WriteLine(MaxSize)
	End Sub
End Class

public class Program
{
    public const string ConstExample = "Constant"; // const string
    public readonly string ReadonlyExample;
    public Program()
    {
        ReadonlyExample = "Initialized at runtime";
    }
    static void Main(string [] args)
    {
        Program p = new Program();
        Console.WriteLine(ConstExample);
        Console.WriteLine(p.ReadonlyExample);
    }
}

Public Class Program
	Public Const ConstExample As String = "Constant" ' const string
	Public ReadOnly ReadonlyExample As String
	Public Sub New()
		ReadonlyExample = "Initialized at runtime"
	End Sub
	Shared Sub Main(ByVal args() As String)
		Dim p As New Program()
		Console.WriteLine(ConstExample)
		Console.WriteLine(p.ReadonlyExample)
	End Sub
End Class

public class Program
{
    static void DemoMethod()
    {
        const int LocalConst = 5; // local constant
        Console.WriteLine(LocalConst);
    }
}

Public Class Program
	Private Shared Sub DemoMethod()
		Const LocalConst As Integer = 5 ' local constant
		Console.WriteLine(LocalConst)
	End Sub
End Class

const double Pi = Math.PI; // This will cause a compile time error

Const Pi As Double = Math.PI ' This will cause a compile time error

public class Calculator
{
    public const int Multiplier = 2;
    public const int DoubleMultiplier = Multiplier * 2; // Constant expression
}

Public Class Calculator
	Public Const Multiplier As Integer = 2
	Public Const DoubleMultiplier As Integer = Multiplier * 2 ' Constant expression
End Class

public class Program
{
    public static readonly string StartTime;
    static Program()
    {
        StartTime = DateTime.Now.ToString("T");
    }
    public static void DisplayStartTime()
    {
        Console.WriteLine($"Program started at: {StartTime}");
    }
}

Public Class Program
	Public Shared ReadOnly StartTime As String
	Shared Sub New()
		StartTime = DateTime.Now.ToString("T")
	End Sub
	Public Shared Sub DisplayStartTime()
		Console.WriteLine($"Program started at: {StartTime}")
	End Sub
End Class

public class Configuration
{
    public static readonly int MaxUsers;
    public const int TimeoutSeconds = 30;
    static Configuration()
    {
        MaxUsers = FetchMaxUsersFromConfig();
    }
    private static int FetchMaxUsersFromConfig()
    {
        // Imagine this method reads from a configuration file
        return 100;
    }
}

Public Class Configuration
	Public Shared ReadOnly MaxUsers As Integer
	Public Const TimeoutSeconds As Integer = 30
	Shared Sub New()
		MaxUsers = FetchMaxUsersFromConfig()
	End Sub
	Private Shared Function FetchMaxUsersFromConfig() As Integer
		' Imagine this method reads from a configuration file
		Return 100
	End Function
End Class

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;
public class PdfGenerator
{
    // Defining a constant HTML template
    public const string HtmlTemplate = @"
        <html>
            <head>
                <title>PDF Report</title>
            </head>
            <body>
                <h1>IronPDF Report</h1>
                <p>This is a simple PDF document generated from HTML string using IronPDF.</p>
            </body>
        </html>";
    public static void CreatePdf(string filePath)
    {
        IronPdf.License.LicenseKey = "License";
        // Create a new PDF document from HTML template
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf(HtmlTemplate);
        // Save the PDF document to a file
        pdf.SaveAs(filePath);
        Console.WriteLine($"PDF generated successfully at {filePath}");
    }
}
class Program
{
    static void Main(string [] args)
    {
        PdfGenerator.CreatePdf("example.pdf");
    }
}

Imports IronPdf
Public Class PdfGenerator
	' Defining a constant HTML template
	Public Const HtmlTemplate As String = "
        <html>
            <head>
                <title>PDF Report</title>
            </head>
            <body>
                <h1>IronPDF Report</h1>
                <p>This is a simple PDF document generated from HTML string using IronPDF.</p>
            </body>
        </html>"
	Public Shared Sub CreatePdf(ByVal filePath As String)
		IronPdf.License.LicenseKey = "License"
		' Create a new PDF document from HTML template
		Dim renderer = New ChromePdfRenderer()
		Dim pdf = renderer.RenderHtmlAsPdf(HtmlTemplate)
		' Save the PDF document to a file
		pdf.SaveAs(filePath)
		Console.WriteLine($"PDF generated successfully at {filePath}")
	End Sub
End Class
Friend Class Program
	Shared Sub Main(ByVal args() As String)
		PdfGenerator.CreatePdf("example.pdf")
	End Sub
End Class