為什麼我不能在C#中使用StreamReader讀取Excel文件？

StreamReader是為讀取文字文件而設計的，不支援Excel文件的二進制格式，這會導致字元篡改或異常。

在C#中讀取Excel文件的推薦方法是什麼？

在C#中讀取Excel文件的推薦方法是使用IronXL，它可以在不需要Excel Interop的情況下直接讀取和操控Excel文件。

IronXL相比於StreamReader處理Excel文件有什麼優勢？

IronXL專門設計來處理Excel文件格式，允許準確的資料讀取和操控，支援公式、圖表和格式等多種功能。

我需要Excel Interop才能使用IronXL嗎？

不，IronXL是獨立於Excel Interop運行的，允許您在未安裝Excel的情況下處理Excel文件。

IronXL能處理不同的Excel文件格式嗎？

是的，IronXL支援多種Excel文件格式，包括.xls、.xlsx和.csv，提供了處理各類Excel文件的靈活性。

IronXL 適合處理大型 Excel 文件嗎？

是的，IronXL針對性能進行了優化，能夠有效地處理大型Excel文件，非常適合處理大量資料的應用。

IronXL與其他C# Excel操控程式庫相比如何？

IronXL提供了使用者友好的API，對Excel功能提供了全面的支援，且不需要安裝Excel，使其相比其他程式庫成為一個強而有力的選擇。

How does IronXL handle different Excel file formats?

IronXL automatically detects and loads different Excel file formats like XLSX, XLS, XLSM, and CSV. It handles all the complex parsing internally, allowing you to focus on data manipulation without worrying about format variations.

Is IronXL capable of data transformation and integration with databases?

Yes, IronXL can transform worksheet data into a DataTable, enabling integration with databases and data-binding scenarios. This feature is particularly useful for applications that require seamless data management and manipulation.

What makes IronXL an effective tool for Excel file processing?

IronXL is effective due to its intuitive API, comprehensive support for various file formats, and robust stream processing capabilities. It's designed to handle Excel files reliably across different environments, making it ideal for diverse application needs.

C# Excel 程式庫

Explore IronXL C# .NET 的 Excel 試算表程式庫開始免費試用

無需 Interop 即可讀取 Excel 檔案

查看所有程式碼範例

using IronXL;
using System;
using System.Linq;

// Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Select worksheet at index 0
WorkSheet workSheet = workBook.WorkSheets[0];

// Get any existing worksheet
WorkSheet firstSheet = workBook.DefaultWorkSheet;

// Select a cell and return the converted value
int cellValue = workSheet["A2"].IntValue;

// Read from ranges of cells elegantly.
foreach (var cell in workSheet["A2:A10"])
{
    Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text);
}

// Calculate aggregate values such as Min, Max and Sum
decimal sum = workSheet["A2:A10"].Sum();

// Linq compatible
decimal max = workSheet["A2:A10"].Max(c => c.DecimalValue);

using IronXL;
using System;
using System.Linq;

// Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.Load("sample.xlsx");

// Select worksheet at index 0
WorkSheet workSheet = workBook.WorkSheets[0];

// Get any existing worksheet
WorkSheet firstSheet = workBook.DefaultWorkSheet;

// Select a cell and return the converted value
int cellValue = workSheet["A2"].IntValue;

// Read from ranges of cells elegantly.
foreach (var cell in workSheet["A2:A10"])
{
    Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text);
}

// Calculate aggregate values such as Min, Max and Sum
decimal sum = workSheet["A2:A10"].Sum();

// Linq compatible
decimal max = workSheet["A2:A10"].Max(c => c.DecimalValue);

PM >Install-Package IronXL.Excel

Install-Package IronXL.Excel

USING IRONXL

C# 中讀取 Excel 檔案的 StreamReader 替代方案 - IronXL

Curtis Chau

Updated: 2026年1月5日

許多C#開發人員在嘗試讀取Excel工作表文件時遇到一個常見的挑戰：他們所信賴的StreamReader在處理文字文件時運行良好，但在Excel文件上卻神秘地失敗了。如果您嘗試使用StreamReader在C#中讀取Excel文件時出現亂碼或異常，您並不孤單。本教程解釋了為什麼StreamReader不能直接處理Excel文件，並展示如何使用IronXL而不依賴Excel Interop的正確解決方案。

混淆常常出現在CSV文件可以被Excel打開且與StreamReader合作良好的情況中。然而，真正的Excel文件（XLSX，XLS）需要截然不同的方法。理解這一區別將節省您數小時的除錯時間，並引導您找到正確的工具。

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 1－IronXL

為什麼StreamReader無法讀取Excel文件？

StreamReader專為純文字文件設計，逐行根據指定的編碼讀取字元資料。儘管Excel文件的外觀像是電子表格，但實際上它們是複雜的二進位或ZIP壓縮的XML結構，StreamReader無法解釋這類文件。

static void Main(string[] args)
{
    // This code will NOT work - demonstrates the problem
    using (StreamReader reader = new StreamReader("ProductData.xlsx"))
    {
        string content = reader.ReadLine(); // read data
        Console.WriteLine(content); // Outputs garbled binary data
    }
}

static void Main(string[] args)
{
    // This code will NOT work - demonstrates the problem
    using (StreamReader reader = new StreamReader("ProductData.xlsx"))
    {
        string content = reader.ReadLine(); // read data
        Console.WriteLine(content); // Outputs garbled binary data
    }
}

Option Strict On
Option Infer On

Imports System.IO

Module Program
    Sub Main(args As String())
        ' This code will NOT work - demonstrates the problem
        Using reader As New StreamReader("ProductData.xlsx")
            Dim content As String = reader.ReadLine() ' read data
            Console.WriteLine(content) ' Outputs garbled binary data
        End Using
    End Sub
End Module

Option Strict On
Option Infer On

Imports System.IO

Module Program
    Sub Main(args As String())
        ' This code will NOT work - demonstrates the problem
        Using reader As New StreamReader("ProductData.xlsx")
            Dim content As String = reader.ReadLine() ' read data
            Console.WriteLine(content) ' Outputs garbled binary data
        End Using
    End Sub
End Module

當您運行此類程式程式碼片段時，您將會見到的不是您的表格資料，而是未知的二進位資料，例如"PK♥♦"或類似的系統字元。這種情況發生是因為XLSX文件是包含多個XML文件的ZIP檔案，而XLS文件則使用專有的二進位格式。 StreamReader期望的是純文字，並嘗試將這些複雜的結構解釋為字元，導致無意義的輸出。

範例輸入

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 2－Excel Input

輸出

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 3－控制台輸出

現代Excel文件（XLSX）包括多個組件：工作表、樣式、共享字串和關係，所有這些都被打包在一起。這種複雜性需要能理解Excel文件結構的專用程式庫，這就引出了IronXL。

如何使用 IronXL 讀取 Excel 檔案？

IronXL為C#中讀取Excel文件提供了一個簡單的解決方案。與StreamReader不同，IronXL了解Excel的內部結構，並提供方便的方法來存取您的資料。該程式庫支持Windows、Linux、macOS和Docker容器，使其成為當前跨平台應用程式的理想選擇。

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 4－跨平台

首先，通過NuGet包管理器安裝IronXL：

PM > Install-Package IronXL.Excel

Install-Package IronXL.Excel

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 5－安裝

這是如何正確讀取Excel文件的方法：

using IronXL;
// Load the Excel file
WorkBook workbook = WorkBook.Load("sample.xlsx");
WorkSheet worksheet = workbook.DefaultWorkSheet;
// Read specific cell values
string cellValue = worksheet["A1"].StringValue;
Console.WriteLine($"Cell A1 contains: {cellValue}");
// Read a range of cells
foreach (var cell in worksheet["A1:C5"])
{
    Console.WriteLine($"{cell.AddressString}: {cell.Text}");
}

using IronXL;
// Load the Excel file
WorkBook workbook = WorkBook.Load("sample.xlsx");
WorkSheet worksheet = workbook.DefaultWorkSheet;
// Read specific cell values
string cellValue = worksheet["A1"].StringValue;
Console.WriteLine($"Cell A1 contains: {cellValue}");
// Read a range of cells
foreach (var cell in worksheet["A1:C5"])
{
    Console.WriteLine($"{cell.AddressString}: {cell.Text}");
}

Imports IronXL

' Load the Excel file
Dim workbook As WorkBook = WorkBook.Load("sample.xlsx")
Dim worksheet As WorkSheet = workbook.DefaultWorkSheet
' Read specific cell values
Dim cellValue As String = worksheet("A1").StringValue
Console.WriteLine($"Cell A1 contains: {cellValue}")
' Read a range of cells
For Each cell In worksheet("A1:C5")
    Console.WriteLine($"{cell.AddressString}: {cell.Text}")
Next

Imports IronXL

' Load the Excel file
Dim workbook As WorkBook = WorkBook.Load("sample.xlsx")
Dim worksheet As WorkSheet = workbook.DefaultWorkSheet
' Read specific cell values
Dim cellValue As String = worksheet("A1").StringValue
Console.WriteLine($"Cell A1 contains: {cellValue}")
' Read a range of cells
For Each cell In worksheet("A1:C5")
    Console.WriteLine($"{cell.AddressString}: {cell.Text}")
Next

此程式碼成功載入您的Excel文件，並提供對單元格值的清晰存取。 WorkBook.Load方法會自動檢測文件格式（XLSX，XLS，XLSM，CSV）並在內部處理所有複雜的解析。您可以使用熟悉的Excel表示法（如"A1"）存取單元格，或者使用範圍（如"A1:C5"），這使得對於任何熟悉Excel的人來說程式碼都是可理解的。

如何從記憶體流讀取 Excel？

實際應用程式經常需要從流而非磁碟檔案處理 Excel 檔案。常見的場景包括處理網頁上傳、從資料庫中檢索文件或處理來自雲儲存的資料。 IronXL優雅地處理這些情況：

using IronXL;
using System.IO;
// Read Excel from a memory stream
byte[] fileBytes = File.ReadAllBytes("ProductData.xlsx");
using (MemoryStream stream = new MemoryStream(fileBytes))
{
    WorkBook workbook = WorkBook.FromStream(stream);
    WorkSheet worksheet = workbook.DefaultWorkSheet;
    // Process the data
    int rowCount = worksheet.RowCount;
    Console.WriteLine($"The worksheet has {rowCount} rows");
    // Read all data into a new DataTable, return dt
    var dataTable = worksheet.ToDataTable(false);
    // Return DataTable row count
    Console.WriteLine($"Loaded {dataTable.Rows.Count} data rows");
}

using IronXL;
using System.IO;
// Read Excel from a memory stream
byte[] fileBytes = File.ReadAllBytes("ProductData.xlsx");
using (MemoryStream stream = new MemoryStream(fileBytes))
{
    WorkBook workbook = WorkBook.FromStream(stream);
    WorkSheet worksheet = workbook.DefaultWorkSheet;
    // Process the data
    int rowCount = worksheet.RowCount;
    Console.WriteLine($"The worksheet has {rowCount} rows");
    // Read all data into a new DataTable, return dt
    var dataTable = worksheet.ToDataTable(false);
    // Return DataTable row count
    Console.WriteLine($"Loaded {dataTable.Rows.Count} data rows");
}

Imports IronXL
Imports System.IO

' Read Excel from a memory stream
Dim fileBytes As Byte() = File.ReadAllBytes("ProductData.xlsx")
Using stream As New MemoryStream(fileBytes)
    Dim workbook As WorkBook = WorkBook.FromStream(stream)
    Dim worksheet As WorkSheet = workbook.DefaultWorkSheet
    ' Process the data
    Dim rowCount As Integer = worksheet.RowCount
    Console.WriteLine($"The worksheet has {rowCount} rows")
    ' Read all data into a new DataTable, return dt
    Dim dataTable = worksheet.ToDataTable(False)
    ' Return DataTable row count
    Console.WriteLine($"Loaded {dataTable.Rows.Count} data rows")
End Using

Imports IronXL
Imports System.IO

' Read Excel from a memory stream
Dim fileBytes As Byte() = File.ReadAllBytes("ProductData.xlsx")
Using stream As New MemoryStream(fileBytes)
    Dim workbook As WorkBook = WorkBook.FromStream(stream)
    Dim worksheet As WorkSheet = workbook.DefaultWorkSheet
    ' Process the data
    Dim rowCount As Integer = worksheet.RowCount
    Console.WriteLine($"The worksheet has {rowCount} rows")
    ' Read all data into a new DataTable, return dt
    Dim dataTable = worksheet.ToDataTable(False)
    ' Return DataTable row count
    Console.WriteLine($"Loaded {dataTable.Rows.Count} data rows")
End Using

FileStream還是網路流。這種靈活性允許您在不先將文件保存到磁碟的情況下，從各種來源處理Excel文件。該範例還展示了將工作表資料轉換為資料表，這能與資料庫和資料綁定場景無縫整合。

輸出

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 6－從MemoryStream輸出讀取Excel

何時使用object sender來讀取資料？

在此程式碼用於事件驅動編程（例如，在Windows Forms或ASP.NET中處理文件上傳按鈕）時，單一的方法簽名通常包括像EventArgs e這樣的參數。這樣的上下文確保了Excel處理邏輯正確地與UI或服務事件結合。

使用StreamReader在C#中讀取Excel文件的替代方案－IronXL：Image 7－功能

如何在 Excel 和 CSV 之間轉換？

雖然StreamReader可以處理CSV文件，但通常需要在Excel和CSV格式之間進行轉換。 IronXL使得此轉換簡單易行：

using IronXL;
// Load an Excel file and save as CSV
WorkBook workbook = WorkBook.Load("data.xlsx");
workbook.SaveAsCsv("output.csv");
// Load a CSV file and save as Excel
WorkBook csvWorkbook = WorkBook.LoadCSV("input.csv");
csvWorkbook.SaveAs("output.xlsx");
// Export specific worksheet to CSV
WorkSheet worksheet = workbook.WorkSheets[0];
worksheet.SaveAsCsv("worksheet1.csv");

using IronXL;
// Load an Excel file and save as CSV
WorkBook workbook = WorkBook.Load("data.xlsx");
workbook.SaveAsCsv("output.csv");
// Load a CSV file and save as Excel
WorkBook csvWorkbook = WorkBook.LoadCSV("input.csv");
csvWorkbook.SaveAs("output.xlsx");
// Export specific worksheet to CSV
WorkSheet worksheet = workbook.WorkSheets[0];
worksheet.SaveAsCsv("worksheet1.csv");

Imports IronXL

' Load an Excel file and save as CSV
Dim workbook As WorkBook = WorkBook.Load("data.xlsx")
workbook.SaveAsCsv("output.csv")

' Load a CSV file and save as Excel
Dim csvWorkbook As WorkBook = WorkBook.LoadCSV("input.csv")
csvWorkbook.SaveAs("output.xlsx")

' Export specific worksheet to CSV
Dim worksheet As WorkSheet = workbook.WorkSheets(0)
worksheet.SaveAsCsv("worksheet1.csv")

Imports IronXL

' Load an Excel file and save as CSV
Dim workbook As WorkBook = WorkBook.Load("data.xlsx")
workbook.SaveAsCsv("output.csv")

' Load a CSV file and save as Excel
Dim csvWorkbook As WorkBook = WorkBook.LoadCSV("input.csv")
csvWorkbook.SaveAs("output.xlsx")

' Export specific worksheet to CSV
Dim worksheet As WorkSheet = workbook.WorkSheets(0)
worksheet.SaveAsCsv("worksheet1.csv")

這些轉換在改變文件格式的同時保留了您的資料。在將Excel轉換為CSV時，IronXL預設展開第一個工作表，但您可以指定要導出的工作表。從CSV轉換為Excel時，會建立一個格式正確的電子表格，能保存資料型別並啟用未來的格式和公式新增。