Read a CSV File in C

我為什麼要使用NuGet套件管理器？

在 Visual Studio 中，選擇"項目"選單

• 管理NuGet程式包
• 搜尋IronXl.Excel
• 安裝

圖 1 - IronXl.Excel NuGet包

還有哪些安裝方法？

我需要匯入哪個命名空間？

新增IronXL命名空間：

// This namespace is required to access the IronXL functionalities
using IronXL;

// This namespace is required to access the IronXL functionalities
using IronXL;

如何載入和轉換CSV檔案？

新增程式碼，使用IronXL和 C# 以程式設計方式讀取 CSV 檔案：

:path=/static-assets/excel/content-code-examples/how-to/csharp-read-csv-read.cs

// Load the CSV file into a WorkBook object, specifying the file path, format, and delimiter
WorkBook workbook = WorkBook.LoadCSV("Read_CSV_Ex.csv", fileFormat: ExcelFileFormat.XLSX, listDelimiter: ",");

// Access the default worksheet within the loaded workbook
WorkSheet ws = workbook.DefaultWorkSheet;

// Save the workbook as an Excel file with a specified name
workbook.SaveAs("Csv_To_Excel.xlsx");

有哪些進階 CSV 讀取選項？

IronXL提供處理各種配置的 CSV 檔案的功能。 您可以指定不同的分隔符號(分號、製表符、垂直線)，並處理不同編碼的檔案：

// Example: Reading CSV with custom delimiter and encoding
WorkBook workbook = WorkBook.LoadCSV("data.csv", 
    fileFormat: ExcelFileFormat.XLSX, 
    listDelimiter: ";",  // Using semicolon as delimiter
    encoding: Encoding.UTF8);

// Access specific cells after loading
var cellValue = workbook.DefaultWorkSheet["A1"].Value;

// Iterate through rows
foreach (var row in workbook.DefaultWorkSheet.Rows)
{
    // Process each row
    foreach (var cell in row)
    {
        Console.WriteLine(cell.Value);
    }
}

// Example: Reading CSV with custom delimiter and encoding
WorkBook workbook = WorkBook.LoadCSV("data.csv", 
    fileFormat: ExcelFileFormat.XLSX, 
    listDelimiter: ";",  // Using semicolon as delimiter
    encoding: Encoding.UTF8);

// Access specific cells after loading
var cellValue = workbook.DefaultWorkSheet["A1"].Value;

// Iterate through rows
foreach (var row in workbook.DefaultWorkSheet.Rows)
{
    // Process each row
    foreach (var cell in row)
    {
        Console.WriteLine(cell.Value);
    }
}

處理前的 CSV 檔案是什麼樣的？

圖 2 -記事本中開啟的 CSV 文件

LoadCSV 方法的工作原理是什麼？

已建立一個 Workbook 物件。 LoadCSV 物件的方法指定要讀取的 CSV 檔案、要讀取到的格式以及分隔符號。 在這種情況下，逗號用作分隔符號。

在放置 CSV 內容的位置建立一個 Worksheet 物件。 然後，該文件將以新名稱和新格式儲存。 This process is useful when you need to convert between different spreadsheet formats.

圖 3 -在 Excel 中開啟的 CSV 文件

如何高效處理大型 CSV 檔案？

IronXL針對效能進行了最佳化，能夠高效處理大型 CSV 檔案。 For developers working with substantial datasets, the library offers significant performance improvements in recent versions. 處理大型文件時，請遵循以下最佳實踐：

// Reading large CSV files with memory optimization
WorkBook workbook = WorkBook.LoadCSV("large_dataset.csv", 
    fileFormat: ExcelFileFormat.XLSX, 
    listDelimiter: ",");

// Process data in chunks
var worksheet = workbook.DefaultWorkSheet;
int rowCount = worksheet.RowCount;
int batchSize = 1000;

for (int i = 0; i < rowCount; i += batchSize)
{
    // Process rows in batches
    var endIndex = Math.Min(i + batchSize, rowCount);
    for (int j = i; j < endIndex; j++)
    {
        var row = worksheet.GetRow(j);
        // Process individual row
    }
}

// Reading large CSV files with memory optimization
WorkBook workbook = WorkBook.LoadCSV("large_dataset.csv", 
    fileFormat: ExcelFileFormat.XLSX, 
    listDelimiter: ",");

// Process data in chunks
var worksheet = workbook.DefaultWorkSheet;
int rowCount = worksheet.RowCount;
int batchSize = 1000;

for (int i = 0; i < rowCount; i += batchSize)
{
    // Process rows in batches
    var endIndex = Math.Min(i + batchSize, rowCount);
    for (int j = i; j < endIndex; j++)
    {
        var row = worksheet.GetRow(j);
        // Process individual row
    }
}

如何將CSV資料匯出為其他格式？

讀取 CSV 檔案後，您可能需要將資料匯出為各種格式。 IronXL supports multiple export options including XLSX to CSV conversion, JSON, XML, and HTML. 以下是如何匯出為不同格式的方法：

// Load CSV and export to multiple formats
WorkBook workbook = WorkBook.LoadCSV("input.csv", ExcelFileFormat.XLSX, ",");

// Export to different formats
workbook.SaveAs("output.xlsx"); // Excel format
workbook.SaveAsJson("output.json"); // JSON format
workbook.SaveAsXml("output.xml"); // XML format

// Export specific worksheet to CSV with custom delimiter
workbook.DefaultWorkSheet.SaveAs("output_custom.csv", ";");

// Load CSV and export to multiple formats
WorkBook workbook = WorkBook.LoadCSV("input.csv", ExcelFileFormat.XLSX, ",");

// Export to different formats
workbook.SaveAs("output.xlsx"); // Excel format
workbook.SaveAsJson("output.json"); // JSON format
workbook.SaveAsXml("output.xml"); // XML format

// Export specific worksheet to CSV with custom delimiter
workbook.DefaultWorkSheet.SaveAs("output_custom.csv", ";");

在Web應用程式中處理CSV資料有哪些方法？

For ASP.NET developers, IronXL provides seamless integration for reading CSV files in web applications. 您可以在 MVC 或 Web API 專案中上傳和處理 CSV 檔案：

// Example: Processing uploaded CSV file in ASP.NET
public ActionResult UploadCSV(HttpPostedFileBase file)
{
    if (file != null && file.ContentLength > 0)
    {
        // Save uploaded file temporarily
        var fileName = Path.GetFileName(file.FileName);
        var path = Path.Combine(Server.MapPath("~/App_Data/"), fileName);
        file.SaveAs(path);

        // Load and process CSV
        WorkBook workbook = WorkBook.LoadCSV(path, ExcelFileFormat.XLSX, ",");

        // Convert to DataTable for easy display
        var dataTable = workbook.DefaultWorkSheet.ToDataTable();

        // Clean up temporary file
        System.IO.File.Delete(path);

        return View(dataTable);
    }
    return RedirectToAction("Index");
}

// Example: Processing uploaded CSV file in ASP.NET
public ActionResult UploadCSV(HttpPostedFileBase file)
{
    if (file != null && file.ContentLength > 0)
    {
        // Save uploaded file temporarily
        var fileName = Path.GetFileName(file.FileName);
        var path = Path.Combine(Server.MapPath("~/App_Data/"), fileName);
        file.SaveAs(path);

        // Load and process CSV
        WorkBook workbook = WorkBook.LoadCSV(path, ExcelFileFormat.XLSX, ",");

        // Convert to DataTable for easy display
        var dataTable = workbook.DefaultWorkSheet.ToDataTable();

        // Clean up temporary file
        System.IO.File.Delete(path);

        return View(dataTable);
    }
    return RedirectToAction("Index");
}

如何處理包含複雜資料的CSV檔案？

在處理包含公式、特殊字元或混合資料類型的 CSV 檔案時， IronXL提供了強大的處理功能。 You can work with formulas and format cell data appropriately:

// Handle CSV with special requirements
WorkBook workbook = WorkBook.LoadCSV("complex_data.csv", 
    ExcelFileFormat.XLSX, 
    listDelimiter: ",");

var worksheet = workbook.DefaultWorkSheet;

// Apply formatting to cells
worksheet["A1:A10"].Style.Font.Bold = true;
worksheet["B1:B10"].FormatString = "$#,##0.00"; // Currency format

// Add formulas after loading CSV data
worksheet["D1"].Formula = "=SUM(B1:B10)";

// Handle CSV with special requirements
WorkBook workbook = WorkBook.LoadCSV("complex_data.csv", 
    ExcelFileFormat.XLSX, 
    listDelimiter: ",");

var worksheet = workbook.DefaultWorkSheet;

// Apply formatting to cells
worksheet["A1:A10"].Style.Font.Bold = true;
worksheet["B1:B10"].FormatString = "$#,##0.00"; // Currency format

// Add formulas after loading CSV data
worksheet["D1"].Formula = "=SUM(B1:B10)";

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IronXL API 參考文檔