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FileStream C#（對開發人員的工作方式）

發佈 2024年10月24日

本文將重點介紹FileStream 類別在 C# 中，它如何幫助您進行文件的讀寫操作。我們將探討實際範例，了解 FileStream 的基本運作方式，並學習如何有效管理檔案資料。本指南適合剛開始學習 C# 檔案處理的新手，因此語言將保持初學者友好，同時提供有關在 C# 中處理檔案的詳細說明和介紹。IronPDF 庫以及。

什麼是 FileStream？

C# 中的 FileStream 類提供了一種使用位元組處理檔案的方法。它適用於文件的讀寫操作，使您能夠直接與文件內容互動。這在處理輸入/輸出任務的文件時特別有用，尤其是在操作位元組陣列時。

FileStream 使用案例

FileStream 適用於：

直接從檔案讀取和寫入二進位資料。
高效處理大型檔案。
執行非同步檔案操作。
通過有效利用記憶體來管理系統資源。

基本範例

以下是一個使用 FileStream 開啟檔案、寫入資料，然後讀取的簡單範例：

using System;
using System.IO;
public static void Main()
{
    string path = "example.txt";
    // Creating a FileStream object to handle the file. The file handle is acquired here.
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        byte[] data = System.Text.Encoding.UTF8.GetBytes("Hello, FileStream!");
        fileStream.Write(data, 0, data.Length);
    }
    // Read from the file
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
        string text = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(text);
    }
}

using System;
using System.IO;
public static void Main()
{
    string path = "example.txt";
    // Creating a FileStream object to handle the file. The file handle is acquired here.
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        byte[] data = System.Text.Encoding.UTF8.GetBytes("Hello, FileStream!");
        fileStream.Write(data, 0, data.Length);
    }
    // Read from the file
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
        string text = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(text);
    }
}

Imports System
Imports System.IO
Public Shared Sub Main()
	Dim path As String = "example.txt"
	' Creating a FileStream object to handle the file. The file handle is acquired here.
	Using fileStream As New FileStream(path, FileMode.Create, FileAccess.Write)
		Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes("Hello, FileStream!")
		fileStream.Write(data, 0, data.Length)
	End Using
	' Read from the file
	Using fileStream As New FileStream(path, FileMode.Open, FileAccess.Read)
		Dim buffer(1023) As Byte
		Dim bytesRead As Integer = fileStream.Read(buffer, 0, buffer.Length)
		Dim text As String = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead)
		Console.WriteLine(text)
	End Using
End Sub

VB C#

此範例展示了如何創建一個 FileStream 物件來處理檔案讀寫操作。 FileStream 類別直接讀取和寫入位元組，適合處理大型檔案或二進位資料。我們使用編碼在文本和字節之間進行轉換。

使用 FileStream 寫入數據

要將資料寫入檔案，您將使用 Write 方法。以下是更詳細說明其工作原理的示例：

using System;
using System.IO;
public static void Main()
{
    string path = "output.txt";
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        byte[] buffer = System.Text.Encoding.UTF8.GetBytes("Writing data to FileStream.");
        int offset = 0;
        int count = buffer.Length;
        // Writing data to the file
        fileStream.Write(buffer, offset, count);
    }
}

using System;
using System.IO;
public static void Main()
{
    string path = "output.txt";
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        byte[] buffer = System.Text.Encoding.UTF8.GetBytes("Writing data to FileStream.");
        int offset = 0;
        int count = buffer.Length;
        // Writing data to the file
        fileStream.Write(buffer, offset, count);
    }
}

Imports System
Imports System.IO
Public Shared Sub Main()
	Dim path As String = "output.txt"
	Using fileStream As New FileStream(path, FileMode.Create, FileAccess.Write)
		Dim buffer() As Byte = System.Text.Encoding.UTF8.GetBytes("Writing data to FileStream.")
		Dim offset As Integer = 0
		Dim count As Integer = buffer.Length
		' Writing data to the file
		fileStream.Write(buffer, offset, count)
	End Using
End Sub

VB C#

在這段程式碼中，我們使用 UTF8 編碼將字串轉換為位元組陣列。 Write 方法從當前位置開始將字節陣列寫入文件。(由偏移量決定)寫入指定數量的位元組。

FileMode.Create 會建立一個新檔案，覆寫任何同名的現有檔案。
FileAccess.Write 授予 FileStream 寫入權限。

使用 FileStream 讀取數據

現在，我們來探索如何使用 FileStream 從檔案讀取資料。

using System;
using System.IO;
public static void Main()
{
    // File path
    string path = "output.txt";
    // File Stream Object
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
    // Output Stream
        string output = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(output);
    }
}

using System;
using System.IO;
public static void Main()
{
    // File path
    string path = "output.txt";
    // File Stream Object
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
    // Output Stream
        string output = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(output);
    }
}

Imports System
Imports System.IO
Public Shared Sub Main()
	' File path
	Dim path As String = "output.txt"
	' File Stream Object
	Using fileStream As New FileStream(path, FileMode.Open, FileAccess.Read)
		Dim buffer(1023) As Byte
		Dim bytesRead As Integer = fileStream.Read(buffer, 0, buffer.Length)
	' Output Stream
		Dim output As String = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead)
		Console.WriteLine(output)
	End Using
End Sub

VB C#

在此範例中：

FileMode.Open 開啟一個現有的文件。
Read 方法讀取指定數量的位元組(基於緩衝區大小)並將它們存儲在位元組陣列緩衝區中。
我們使用 Encoding.UTF8.GetString 將位元組數據轉換回字串。

使用 FileStream 管理文件存取

FileStream 類別控制檔案的存取，允許精細調整的檔案控制和系統資源管理。使用 FileStream 時，確保在使用後正確處理流非常重要，可以通過調用 Close 來完成。()手動處理或使用自動釋放流的語句。

處理檔案位置

每次讀取或寫入文件時，FileStream 會追蹤文件中的當前位置。您可以使用 Position 屬性來訪問此位置：

fileStream.Position = 0; // Move to the beginning of the file

fileStream.Position = 0; // Move to the beginning of the file

fileStream.Position = 0 ' Move to the beginning of the file

VB C#

使用 FileStream 進行非同步操作

FileStream 可以用於非同步讀寫操作，透過允許其他程序在文件操作執行時運行來提升性能。以下是一個非同步讀取的基本範例：

using System;
using System.IO;
using System.Threading.Tasks;
public static async Task Main()
{
    // Specified Path
    string path = "output.txt";
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None, 4096, true))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = await fileStream.ReadAsync(buffer, 0, buffer.Length);
        string result = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(result);
    }
}

using System;
using System.IO;
using System.Threading.Tasks;
public static async Task Main()
{
    // Specified Path
    string path = "output.txt";
    using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None, 4096, true))
    {
        byte[] buffer = new byte[1024];
        int bytesRead = await fileStream.ReadAsync(buffer, 0, buffer.Length);
        string result = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead);
        Console.WriteLine(result);
    }
}

Imports System
Imports System.IO
Imports System.Threading.Tasks
Public Shared Async Function Main() As Task
	' Specified Path
	Dim path As String = "output.txt"
	Using fileStream As New FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None, 4096, True)
		Dim buffer(1023) As Byte
		Dim bytesRead As Integer = Await fileStream.ReadAsync(buffer, 0, buffer.Length)
		Dim result As String = System.Text.Encoding.UTF8.GetString(buffer, 0, bytesRead)
		Console.WriteLine(result)
	End Using
End Function

VB C#

ReadAsync 方法异步地读取数据。 FileAccess.Read 和 FileMode.Open 參數控制檔案的存取方式。

處理例外的範例

在使用FileStream時，處理異常是至關重要的，以避免運行時錯誤並正確管理系統資源。以下是讀取或寫入檔案時處理異常的模式：

using System;
using System.IO;
public static void Main()
{
    string path = "nonexistentfile.txt";
    try
    {
        using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
        {
            byte[] buffer = new byte[1024];
            int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
            Console.WriteLine("Bytes Read: " + bytesRead);
        }
    }
    catch (FileNotFoundException e)
    {
        Console.WriteLine($"Exception: {e.Message}");
    }
}

using System;
using System.IO;
public static void Main()
{
    string path = "nonexistentfile.txt";
    try
    {
        using (FileStream fileStream = new FileStream(path, FileMode.Open, FileAccess.Read))
        {
            byte[] buffer = new byte[1024];
            int bytesRead = fileStream.Read(buffer, 0, buffer.Length);
            Console.WriteLine("Bytes Read: " + bytesRead);
        }
    }
    catch (FileNotFoundException e)
    {
        Console.WriteLine($"Exception: {e.Message}");
    }
}

Imports System
Imports System.IO
Public Shared Sub Main()
	Dim path As String = "nonexistentfile.txt"
	Try
		Using fileStream As New FileStream(path, FileMode.Open, FileAccess.Read)
			Dim buffer(1023) As Byte
			Dim bytesRead As Integer = fileStream.Read(buffer, 0, buffer.Length)
			Console.WriteLine("Bytes Read: " & bytesRead)
		End Using
	Catch e As FileNotFoundException
		Console.WriteLine($"Exception: {e.Message}")
	End Try
End Sub

VB C#

緩衝和效能

FileStream 類別包含緩衝機制，使效能更快，特別是在處理大型檔案時。使用緩衝區，數據臨時存儲在記憶體中，減少對磁碟的不斷訪問需求。

using System;
using System.IO;
public static void Main()
{
    string path = "bufferedfile.txt";
    byte[] data = System.Text.Encoding.UTF8.GetBytes("Buffered FileStream example.");
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None, 4096, FileOptions.WriteThrough))
    {
        fileStream.Write(data, 0, data.Length);
    }
}

using System;
using System.IO;
public static void Main()
{
    string path = "bufferedfile.txt";
    byte[] data = System.Text.Encoding.UTF8.GetBytes("Buffered FileStream example.");
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None, 4096, FileOptions.WriteThrough))
    {
        fileStream.Write(data, 0, data.Length);
    }
}

Imports System
Imports System.IO
Public Shared Sub Main()
	Dim path As String = "bufferedfile.txt"
	Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes("Buffered FileStream example.")
	Using fileStream As New FileStream(path, FileMode.Create, FileAccess.Write, FileShare.None, 4096, FileOptions.WriteThrough)
		fileStream.Write(data, 0, data.Length)
	End Using
End Sub

VB C#

在這裡，FileOptions.WriteThrough 確保數據直接寫入文件，繞過額外的緩衝。然而，您可以控制緩衝區大小以進行性能調整。

介紹 IronPDF

FileStream C#（開發人員如何運作）：圖1 - IronPDF：C# PDF程式庫

IronPDF是一個強大的 C# PDF 函式庫，用於在 .NET 應用程式中建立、編輯和操作 PDF 文件。開發人員可以從各種輸入（如HTML）生成PDF檔案、圖像，甚至使用 IronPDF 的原始文本。 IronPDF 提供浮水印、合併、分割和密碼保護等功能，非常適合對 PDF 輸出有精確控制的網頁和桌面應用程式。

IronPDF 與 FileStream

以下是使用 IronPDF 生成 PDF 並將其保存到 FileStream 的範例。這展示了IronPDF如何順利整合FileStream，讓開發人員能夠以程式方式控制PDF的創建和保存。

using System;
using System.IO;
using IronPdf;
public static void Main()
{
    // Define the file path
    string path = "output.pdf";
    // Create an HTML string that we want to convert to PDF
    var htmlContent = "<h1>IronPDF Example</h1><p>This PDF was generated using IronPDF and saved with FileStream.</p>";
    // Initialize IronPDF's ChromePdfRenderer to render HTML as PDF
    var renderer = new ChromePdfRenderer();
    // Generate the PDF from the HTML string
    var pdfDocument = renderer.RenderHtmlAsPdf(htmlContent);
    // Use FileStream to save the generated PDF
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        pdfDocument.SaveAs(fileStream);
    }
    Console.WriteLine("PDF created and saved successfully.");
}

using System;
using System.IO;
using IronPdf;
public static void Main()
{
    // Define the file path
    string path = "output.pdf";
    // Create an HTML string that we want to convert to PDF
    var htmlContent = "<h1>IronPDF Example</h1><p>This PDF was generated using IronPDF and saved with FileStream.</p>";
    // Initialize IronPDF's ChromePdfRenderer to render HTML as PDF
    var renderer = new ChromePdfRenderer();
    // Generate the PDF from the HTML string
    var pdfDocument = renderer.RenderHtmlAsPdf(htmlContent);
    // Use FileStream to save the generated PDF
    using (FileStream fileStream = new FileStream(path, FileMode.Create, FileAccess.Write))
    {
        pdfDocument.SaveAs(fileStream);
    }
    Console.WriteLine("PDF created and saved successfully.");
}

Imports System
Imports System.IO
Imports IronPdf
Public Shared Sub Main()
	' Define the file path
	Dim path As String = "output.pdf"
	' Create an HTML string that we want to convert to PDF
	Dim htmlContent = "<h1>IronPDF Example</h1><p>This PDF was generated using IronPDF and saved with FileStream.</p>"
	' Initialize IronPDF's ChromePdfRenderer to render HTML as PDF
	Dim renderer = New ChromePdfRenderer()
	' Generate the PDF from the HTML string
	Dim pdfDocument = renderer.RenderHtmlAsPdf(htmlContent)
	' Use FileStream to save the generated PDF
	Using fileStream As New FileStream(path, FileMode.Create, FileAccess.Write)
		pdfDocument.SaveAs(fileStream)
	End Using
	Console.WriteLine("PDF created and saved successfully.")
End Sub

VB C#

結論

FileStream C#（開發人員如何使用）：圖 2 - IronPDF 授權頁面

C# 中的 FileStream 類別提供強大的功能來管理文件的輸入和輸出。它允許開發人員高效讀寫數據，控制文件中的當前位置，並通過理解位元組數組、文件路徑和流處理如何相互協作來進行非同步工作。將 FileStream 與 IronPDF 結合使用能夠為開發者提供在 .NET 應用程式中高效處理 PDF 的彈性。無論是生成報告、保存文件，還是處理動態內容，這種組合在創建和存儲 PDF 文件方面提供了精細控制。

IronPDF 提供一個免費試用以及 749 美元的授權費，使其成為滿足專業 PDF 生成需求的一個具有競爭力的解決方案。

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