C# Substring（开发人员如何使用）

public string Substring(int startIndex);
public string Substring(int startIndex, int length);

public String Substring(Integer startIndex)
public String Substring(Integer startIndex, Integer length)

// Main method demonstrating substring extraction
public static void Main(string[] args)
{
    string text = "Hello, world!";
    string substring = text.Substring(7); // Extract from index 7 to the end
    Console.WriteLine(substring);
}

' Main method demonstrating substring extraction
Public Shared Sub Main(ByVal args() As String)
	Dim text As String = "Hello, world!"
	Dim substring As String = text.Substring(7) ' Extract from index 7 to the end
	Console.WriteLine(substring)
End Sub

// Main method demonstrating substring extraction with specified length
public static void Main(string[] args)
{
    string text = "Hello, world!";
    string substring = text.Substring(7, 5); // Starts at index 7, length of 5
    Console.WriteLine(substring);
}

' Main method demonstrating substring extraction with specified length
Public Shared Sub Main(ByVal args() As String)
	Dim text As String = "Hello, world!"
	Dim substring As String = text.Substring(7, 5) ' Starts at index 7, length of 5
	Console.WriteLine(substring)
End Sub

// Example of extracting substrings from an array of strings
string[] array = { "apple", "banana", "orange" };
foreach (string str in array)
{
    string substring = str.Substring(1, 3); // Substring starts from index 1
    Console.WriteLine(substring);
}

' Example of extracting substrings from an array of strings
Dim array() As String = { "apple", "banana", "orange" }
For Each str As String In array
	Dim substring As String = str.Substring(1, 3) ' Substring starts from index 1
	Console.WriteLine(substring)
Next str

// Main method with checks to avoid ArgumentOutOfRangeException
public static void Main(string[] args)
{
    string text = "Hello, world!";
    int startIndex = 7;
    int length = 5;
    if (startIndex >= 0 && startIndex < text.Length && startIndex + length <= text.Length)
    {
        string substring = text.Substring(startIndex, length);
        Console.WriteLine(substring);
    }
    else
    {
        Console.WriteLine("Invalid substring parameters.");
    }
}

' Main method with checks to avoid ArgumentOutOfRangeException
Public Shared Sub Main(ByVal args() As String)
	Dim text As String = "Hello, world!"
	Dim startIndex As Integer = 7
	Dim length As Integer = 5
	If startIndex >= 0 AndAlso startIndex < text.Length AndAlso startIndex + length <= text.Length Then
		Dim substring As String = text.Substring(startIndex, length)
		Console.WriteLine(substring)
	Else
		Console.WriteLine("Invalid substring parameters.")
	End If
End Sub

using IronPdf;
using System;

public class PdfGenerator
{
    public static void Main(string[] args)
    {
        // Applying your license for IronPDF
        License.LicenseKey = "License-Key";
        // Original large text from which we need to extract information
        string originalText = "IronPDF helps you generate PDF documents in .NET applications easily. Discover more about IronPDF at the official site.";
        // Using the Substring method to extract the part of the string that talks about IronPDF
        string importantInfo = originalText.Substring(0, 65);  // Extracts the first sentence

        // Create a PDF document with IronPDF
        var renderer = new ChromePdfRenderer();
        // Convert the extracted text to PDF
        PdfDocument pdf = renderer.RenderHtmlAsPdf($"<h1>Extracted Information</h1><p>{importantInfo}</p>");
        // Save the PDF to a file
        pdf.SaveAs("ExtractedInfo.pdf");
        // Confirmation output
        Console.WriteLine("PDF generated successfully with extracted information.");
    }
}

Imports IronPdf
Imports System

Public Class PdfGenerator
	Public Shared Sub Main(ByVal args() As String)
		' Applying your license for IronPDF
		License.LicenseKey = "License-Key"
		' Original large text from which we need to extract information
		Dim originalText As String = "IronPDF helps you generate PDF documents in .NET applications easily. Discover more about IronPDF at the official site."
		' Using the Substring method to extract the part of the string that talks about IronPDF
		Dim importantInfo As String = originalText.Substring(0, 65) ' Extracts the first sentence

		' Create a PDF document with IronPDF
		Dim renderer = New ChromePdfRenderer()
		' Convert the extracted text to PDF
		Dim pdf As PdfDocument = renderer.RenderHtmlAsPdf($"<h1>Extracted Information</h1><p>{importantInfo}</p>")
		' Save the PDF to a file
		pdf.SaveAs("ExtractedInfo.pdf")
		' Confirmation output
		Console.WriteLine("PDF generated successfully with extracted information.")
	End Sub
End Class