C# 字串方法大全（開發者完整指南）

string text1 = "Hello";
string text2 = "World";
string result = text1 + " " + text2;  // Output: "Hello World"

Dim text1 As String = "Hello"
Dim text2 As String = "World"
Dim result As String = text1 & " " & text2 ' Output: "Hello World"

var pdfText = "Header: " + extractedHeader + "\n" + "Body: " + extractedBody;

Imports Microsoft.VisualBasic

Dim pdfText = "Header: " & extractedHeader & vbLf & "Body: " & extractedBody

string htmlContent = "<h1>" + headerText + "</h1>" + "<p>" + bodyText + "</p>";

Dim htmlContent As String = "<h1>" & headerText & "</h1>" & "<p>" & bodyText & "</p>"

PdfDocument pdf = HtmlToPdf.ConvertHtmlString(htmlContent);
pdf.SaveAs("formattedDocument.pdf");

Dim pdf As PdfDocument = HtmlToPdf.ConvertHtmlString(htmlContent)
pdf.SaveAs("formattedDocument.pdf")

string documentText = "Invoice Number: 12345";
bool containsInvoiceNumber = documentText.Contains("Invoice Number");

Dim documentText As String = "Invoice Number: 12345"
Dim containsInvoiceNumber As Boolean = documentText.Contains("Invoice Number")

string str = "Invoice Number: 12345";
int position = str.IndexOf('5'); // Returns the position of the first '5'

Dim str As String = "Invoice Number: 12345"
Dim position As Integer = str.IndexOf("5"c) ' Returns the position of the first '5'

using System.Text.RegularExpressions;

string text = "Date: 02/11/2025";
Match match = Regex.Match(text, @"\d{2}/\d{2}/\d{4}");
if (match.Success)
{
    string date = match.Value;  // Output: "02/11/2025"
}

Imports System.Text.RegularExpressions

Private text As String = "Date: 02/11/2025"
Private match As Match = Regex.Match(text, "\d{2}/\d{2}/\d{4}")
If match.Success Then
	Dim [date] As String = match.Value ' Output: "02/11/2025"
End If

StringBuilder sb = new StringBuilder();
sb.AppendLine("Header: " + headerText);
sb.AppendLine("Content: " + bodyText);
string finalText = sb.ToString();

Dim sb As New StringBuilder()
sb.AppendLine("Header: " & headerText)
sb.AppendLine("Content: " & bodyText)
Dim finalText As String = sb.ToString()

string str1 = "Invoice";
string str2 = "Invoice";
bool isMatch = str1.Equals(str2); // Returns true as both have the same value

Dim str1 As String = "Invoice"
Dim str2 As String = "Invoice"
Dim isMatch As Boolean = str1.Equals(str2) ' Returns true as both have the same value

string unicodeStr = "Hello * World";
int unicodePosition = unicodeStr.IndexOf('*'); // Finds the position of the unicode character

Dim unicodeStr As String = "Hello * World"
Dim unicodePosition As Integer = unicodeStr.IndexOf("*"c) ' Finds the position of the unicode character

char[] unicodeArray = "Hello * World".ToCharArray();

Dim unicodeArray() As Char = "Hello * World".ToCharArray()

string sentence = "Total: $45.00";
string totalAmount = sentence.Substring(7); // Extracts "$45.00"

Dim sentence As String = "Total: $45.00"
Dim totalAmount As String = sentence.Substring(7) ' Extracts "$45.00"

using IronPdf;
using System;
using System.Text;

class Program
{
    static void Main()
    {
        // Sample customer data
        string customerName = "John Doe";
        string customerAddress = "123 Main Street, Springfield, IL 62701";
        string[] purchasedItems = { "Item 1 - $10.00", "Item 2 - $20.00", "Item 3 - $30.00" };

        // Start building the HTML content for the invoice
        StringBuilder invoiceContent = new StringBuilder();

        // Adding the header
        invoiceContent.AppendLine("<h1>Invoice</h1>");
        invoiceContent.AppendLine("<h2>Customer Details</h2>");
        invoiceContent.AppendLine("<p><strong>Name:</strong> " + customerName + "</p>");
        invoiceContent.AppendLine("<p><strong>Address:</strong> " + customerAddress + "</p>");

        // Adding the list of purchased items
        invoiceContent.AppendLine("<h3>Items Purchased</h3>");
        invoiceContent.AppendLine("<ul>");
        foreach (var item in purchasedItems)
        {
            invoiceContent.AppendLine("<li>" + item + "</li>");
        }
        invoiceContent.AppendLine("</ul>");

        // Calculate total cost (basic manipulation with string methods)
        double totalCost = 0;
        foreach (var item in purchasedItems)
        {
            string priceString = item.Substring(item.LastIndexOf('$') + 1);
            double price = Convert.ToDouble(priceString);
            totalCost += price;
        }

        // Adding total cost
        invoiceContent.AppendLine("<p><strong>Total Cost:</strong> $" + totalCost.ToString("F2") + "</p>");

        // Convert the HTML to PDF using IronPDF
        var pdf = HtmlToPdf.ConvertHtmlString(invoiceContent.ToString());

        // Save the generated PDF
        pdf.SaveAs("Invoice_Johndoe.pdf");
        Console.WriteLine("Invoice PDF generated successfully.");
    }
}

Imports IronPdf
Imports System
Imports System.Text

Friend Class Program
	Shared Sub Main()
		' Sample customer data
		Dim customerName As String = "John Doe"
		Dim customerAddress As String = "123 Main Street, Springfield, IL 62701"
		Dim purchasedItems() As String = { "Item 1 - $10.00", "Item 2 - $20.00", "Item 3 - $30.00" }

		' Start building the HTML content for the invoice
		Dim invoiceContent As New StringBuilder()

		' Adding the header
		invoiceContent.AppendLine("<h1>Invoice</h1>")
		invoiceContent.AppendLine("<h2>Customer Details</h2>")
		invoiceContent.AppendLine("<p><strong>Name:</strong> " & customerName & "</p>")
		invoiceContent.AppendLine("<p><strong>Address:</strong> " & customerAddress & "</p>")

		' Adding the list of purchased items
		invoiceContent.AppendLine("<h3>Items Purchased</h3>")
		invoiceContent.AppendLine("<ul>")
		For Each item In purchasedItems
			invoiceContent.AppendLine("<li>" & item & "</li>")
		Next item
		invoiceContent.AppendLine("</ul>")

		' Calculate total cost (basic manipulation with string methods)
		Dim totalCost As Double = 0
		For Each item In purchasedItems
			Dim priceString As String = item.Substring(item.LastIndexOf("$"c) + 1)
			Dim price As Double = Convert.ToDouble(priceString)
			totalCost += price
		Next item

		' Adding total cost
		invoiceContent.AppendLine("<p><strong>Total Cost:</strong> $" & totalCost.ToString("F2") & "</p>")

		' Convert the HTML to PDF using IronPDF
		Dim pdf = HtmlToPdf.ConvertHtmlString(invoiceContent.ToString())

		' Save the generated PDF
		pdf.SaveAs("Invoice_Johndoe.pdf")
		Console.WriteLine("Invoice PDF generated successfully.")
	End Sub
End Class