C# Null-Koaleszenz (Wie es für Entwickler funktioniert)

Syntax

The following is the syntax for the null-coalescing operator:

result = expression1 ?? expression2;

result = expression1 ?? expression2;

result = If(expression1, expression2)

• expression1: A null value might be produced by this expression.
• expression2: If expression1 is null, this is the default value or substitute expression to be used.
• result: The variable holding the coalescing operation's outcome.

The null-coalescing operator offers a condensed method of assigning a default value when working with nullable types, which is its main goal in streamlining code and efficiently handling null data.

Benefits

• Conciseness: Handles null checks without requiring complex conditional statements or ternary operators.
• Code readability: Improved by explicitly stating that a default value would be provided if null is returned.

It's crucial to make sure the expression types being compared match or are compatible before using the null-coalescing operator.

Although useful, overusing the operator might make code harder to comprehend. Use it sparingly when it enhances code clarity.

When working with nullable types or scenarios requiring default values, the null-coalescing operator (??) in C# is an effective tool for managing null values and may help write more succinct and understandable code.

The null-coalescing operator ?? possesses the following type-related qualities:

Result Type Inference

The outcome type of the null-coalescing operator is the same as these operands if expressions 1 and 2 have the same type as shown in the following code.

int? Value = null;
int result = Value ?? 10;

int? Value = null;
int result = Value ?? 10;

Dim Value? As Integer = Nothing
Dim result As Integer = If(Value, 10)

Type Compatibility

The outcome type is the type to which both expressions can be implicitly converted if expressions 1 and 2 have distinct types but one can be implicitly converted to the other.

double? value = null;
int result = (int)(value ?? 5.5);

double? value = null;
int result = (int)(value ?? 5.5);

Imports System

Dim value? As Double = Nothing
Dim result As Integer = CInt(Math.Truncate(If(value, 5.5)))

Type Promotion

If the types of expressions 1 and 2 cannot be implicitly converted, the result type will be chosen following C#'s type promotion rules.

int? value = null;
long result = value ?? 100L;

int? value = null;
long result = value ?? 100L;

Dim value? As Integer = Nothing
Dim result As Long = If(value, 100L)

Consequently, the types of the operands involved and the C# type conversion rules dictate the type of variable or expression that holds the result of the null-coalescing operator (??). To guarantee the correct handling of types and values while employing the null-coalescing operator, it's crucial to take compatibility and probable type conversions into account.

Install IronPDF

To install the IronPDF library, enter the following code into the Package Manager:

Install-Package IronPdf

Alternatively, you may use the NuGet Package Manager to search for the package "IronPDF". You may choose and download the necessary package from this list of all the NuGet packages connected to IronPDF.

Create PDF with Null Coalescing

A C# library called IronPDF is used to create and work with PDF documents. The library offers features for working with PDFs, such as formatting, text processing, and image management. "Null-coalescing" is not a method or feature that is exclusive to IronPDF; rather, it is a language feature rather than a library-specific operation.

However, if you are working with IronPDF or any other library in your C# code, you may utilize the null-coalescing operators (??) that the C# language provides.

To handle null situations or provide default values, for example, while working with IronPDF objects, nullable value types or properties that may return null, you can use the null-coalescing operator.

The following example shows how the null-coalescing operator may be used with IronPDF:

using IronPdf;
using IronPdf.Pages;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            int? x = null;

            // Use the null-coalescing operator to provide a default value if x is null
            var outputstr = $@"square of <b>{x}</b> is <b>{Math.Sqrt(x ?? 30)}</b>";

            // Render the HTML string as a PDF using IronPDF
            var pdfcreate = ChromePdfRenderer.StaticRenderHtmlAsPdf(outputstr);

            // Save the generated PDF to the file system
            pdfcreate.SaveAs("demo.pdf");

            // Wait for a key press to prevent the console from closing immediately
            Console.ReadKey();
        }
    }
}

using IronPdf;
using IronPdf.Pages;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            int? x = null;

            // Use the null-coalescing operator to provide a default value if x is null
            var outputstr = $@"square of <b>{x}</b> is <b>{Math.Sqrt(x ?? 30)}</b>";

            // Render the HTML string as a PDF using IronPDF
            var pdfcreate = ChromePdfRenderer.StaticRenderHtmlAsPdf(outputstr);

            // Save the generated PDF to the file system
            pdfcreate.SaveAs("demo.pdf");

            // Wait for a key press to prevent the console from closing immediately
            Console.ReadKey();
        }
    }
}

Imports IronPdf
Imports IronPdf.Pages

Namespace ConsoleApp1
	Friend Class Program
		Shared Sub Main(ByVal args() As String)
			Dim x? As Integer = Nothing

			' Use the null-coalescing operator to provide a default value if x is null
			Dim outputstr = $"square of <b>{x}</b> is <b>{Math.Sqrt(If(x, 30))}</b>"

			' Render the HTML string as a PDF using IronPDF
			Dim pdfcreate = ChromePdfRenderer.StaticRenderHtmlAsPdf(outputstr)

			' Save the generated PDF to the file system
			pdfcreate.SaveAs("demo.pdf")

			' Wait for a key press to prevent the console from closing immediately
			Console.ReadKey()
		End Sub
	End Class
End Namespace

Remember that IronPDF (or any library) does not provide a special feature or method for managing null values conditional operators; rather, the usage of the null-coalescing operator is based on general C# language features and concepts for handling a null conditional operator. To know more about the features and capabilities of IronPDF, visit the IronPDF Demos.

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