如何使用高效的 C# CSV 解析器简化数据处理，IronXL

string line = "John,Doe,30,Engineer";
string[] values = line.Split(','); // string array

Dim line As String = "John,Doe,30,Engineer"
Dim values As String() = line.Split(","c) ' string array

dotnet add package IronXL.Excel

using IronXL;

Imports IronXL

// Load a CSV file
var reader = WorkBook.LoadCSV("customers.csv");
// Access the default worksheet (CSV files have one sheet)
WorkSheet sheet = reader.DefaultWorkSheet;
// Read a specific cell value
string customerName = sheet["B2"].StringValue;
// Display the value
Console.WriteLine($"Customer: {customerName}");

Imports IronXL

' Load a CSV file
Dim reader = WorkBook.LoadCSV("customers.csv")
' Access the default worksheet (CSV files have one sheet)
Dim sheet As WorkSheet = reader.DefaultWorkSheet
' Read a specific cell value
Dim customerName As String = sheet("B2").StringValue
' Display the value
Console.WriteLine($"Customer: {customerName}")

// Load CSV with automatic delimiter detection
WorkBook workbook = WorkBook.LoadCSV("sales_data.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Iterate through rows
for (var row = 1; row <= sheet.RowCount; row++)
{
    // Read cells in the current row
    string productName = sheet[$"A{row}"].StringValue;
    decimal price = sheet[$"B{row}"].DecimalValue;
    int quantity = sheet[$"C{row}"].IntValue;
    Console.WriteLine($"Product: {productName}, Price: ${price}, Qty: {quantity}");
}

Imports System

' Load CSV with automatic delimiter detection
Dim workbook As WorkBook = WorkBook.LoadCSV("sales_data.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Iterate through rows
For row As Integer = 1 To sheet.RowCount
    ' Read cells in the current row
    Dim productName As String = sheet($"A{row}").StringValue
    Dim price As Decimal = sheet($"B{row}").DecimalValue
    Dim quantity As Integer = sheet($"C{row}").IntValue
    Console.WriteLine($"Product: {productName}, Price: ${price}, Qty: {quantity}")
Next row

// Load a tab-separated file
WorkBook workbook = WorkBook.LoadCSV("inventory.tsv", 
    fileFormat: ExcelFileFormat.XLSX, 
    listDelimiter: "\t");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Process header row
var headers = new List<string>();
for (int col = 0; col < sheet.ColumnCount; col++)
{
    headers.Add(sheet.GetCellAt(0, col).StringValue);
}
// Display headers
Console.WriteLine("Columns: " + string.Join(" | ", headers));

Imports System
Imports IronXL

' Load a tab-separated file
Dim workbook As WorkBook = WorkBook.LoadCSV("inventory.tsv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:=vbTab)
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Process header row
Dim headers As New List(Of String)()
For col As Integer = 0 To sheet.ColumnCount - 1
    headers.Add(sheet.GetCellAt(0, col).StringValue)
Next
' Display headers
Console.WriteLine("Columns: " & String.Join(" | ", headers))

var csv = WorkBook.LoadCSV("employees.csv");
WorkSheet sheet = csv.DefaultWorkSheet;
// Read a range of cells
var range = sheet["A2:D10"];
// Process all cells in the range
foreach (var cell in range)
{
    if (!cell.IsEmpty)
    {
        Console.WriteLine($"Cell {cell.AddressString}: {cell.Text}");
    }
}
// Calculate sum of a numeric column
decimal totalSalary = sheet["E2:E100"].Sum();
Console.WriteLine($"Total Salary: ${totalSalary:N2}");

Imports System

Dim csv = WorkBook.LoadCSV("employees.csv")
Dim sheet As WorkSheet = csv.DefaultWorkSheet
' Read a range of cells
Dim range = sheet("A2:D10")
' Process all cells in the range
For Each cell In range
    If Not cell.IsEmpty Then
        Console.WriteLine($"Cell {cell.AddressString}: {cell.Text}")
    End If
Next
' Calculate sum of a numeric column
Dim totalSalary As Decimal = sheet("E2:E100").Sum()
Console.WriteLine($"Total Salary: ${totalSalary:N2}")

WorkBook workbook = WorkBook.LoadCSV("products_with_headers.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Skip header row and process var data
for (int row = 1; row <= sheet.RowCount; row++)
{
    var rowData = sheet.GetRow(row);
    // Access cells by index based on known column positions
    string sku = rowData.Columns[0].StringValue;      // Column A
    string description = rowData.Columns[1].StringValue; // Column B
    decimal cost = rowData.Columns[2].DecimalValue;    // Column C
    // Process the data
    ProcessProduct(sku, description, cost);
}
void ProcessProduct(string sku, string description, decimal cost)
{
    // Business logic here
    Console.WriteLine($"Processing: {sku} - {description} (${cost})");
}

Imports System

Dim workbook As WorkBook = WorkBook.LoadCSV("products_with_headers.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Skip header row and process data
For row As Integer = 1 To sheet.RowCount
    Dim rowData = sheet.GetRow(row)
    ' Access cells by index based on known column positions
    Dim sku As String = rowData.Columns(0).StringValue ' Column A
    Dim description As String = rowData.Columns(1).StringValue ' Column B
    Dim cost As Decimal = rowData.Columns(2).DecimalValue ' Column C
    ' Process the data
    ProcessProduct(sku, description, cost)
Next

Sub ProcessProduct(sku As String, description As String, cost As Decimal)
    ' Business logic here
    Console.WriteLine($"Processing: {sku} - {description} (${cost})")
End Sub

// CSV with complex quoted fields
string csvContent = @"Name,Description,Price,Category
""Johnson, Mike"",""Premium keyboard with ""mechanical"" switches"",149.99,Electronics
""O'Brien, Sarah"",""Children's toy - ages 3+"",29.99,Toys";
// Save content to file for demonstration
File.WriteAllText("complex_data.csv", csvContent);
// Load and process the CSV
WorkBook workbook = WorkBook.LoadCSV("complex_data.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Read the complex fields
for (int row = 1; row <= sheet.RowCount; row++)
{
    string name = sheet[$"A{row}"].StringValue;
    string description = sheet[$"B{row}"].StringValue;
    Console.WriteLine($"Name: {name}");
    Console.WriteLine($"Description: {description}");
    Console.WriteLine("---");
}

Imports System
Imports System.IO

' CSV with complex quoted fields
Dim csvContent As String = "Name,Description,Price,Category" & vbCrLf &
    """Johnson, Mike"",""Premium keyboard with """"mechanical"""" switches"",149.99,Electronics" & vbCrLf &
    """O'Brien, Sarah"",""Children's toy - ages 3+"",29.99,Toys"
' Save content to file for demonstration
File.WriteAllText("complex_data.csv", csvContent)
' Load and process the CSV
Dim workbook As WorkBook = WorkBook.LoadCSV("complex_data.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Read the complex fields
For row As Integer = 1 To sheet.RowCount
    Dim name As String = sheet($"A{row}").StringValue
    Dim description As String = sheet($"B{row}").StringValue
    Console.WriteLine($"Name: {name}")
    Console.WriteLine($"Description: {description}")
    Console.WriteLine("---")
Next row

// Load CSV with specific encoding
WorkBook workbook = WorkBook.Load("international_data.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Process international characters
for (int row = 1; row <= sheet.RowCount; row++)
{
    string city = sheet[$"A{row}"].StringValue;
    string country = sheet[$"B{row}"].StringValue;
    // Characters like ñ, ü, é display correctly
    Console.WriteLine($"Location: {city}, {country}");
}
// Save with UTF-8 encoding to preserve characters
workbook.SaveAsCsv("output_utf8.csv");

Imports IronXL

' Load CSV with specific encoding
Dim workbook As WorkBook = WorkBook.Load("international_data.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Process international characters
For row As Integer = 1 To sheet.RowCount
    Dim city As String = sheet($"A{row}").StringValue
    Dim country As String = sheet($"B{row}").StringValue
    ' Characters like ñ, ü, é display correctly
    Console.WriteLine($"Location: {city}, {country}")
Next
' Save with UTF-8 encoding to preserve characters
workbook.SaveAsCsv("output_utf8.csv")

// European CSV format (semicolon delimiter, comma decimal)
string europeanCsv = @"Product;Price;Quantity
Widget A;12,50;100
Gadget B;24,99;50";
File.WriteAllText("european.csv", europeanCsv);
// Load with semicolon delimiter
WorkBook workbook = WorkBook.LoadCSV("european.csv", 
    fileFormat: ExcelFileFormat.XLSX,
    listDelimiter: ";");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Parse European number format
for (int row = 1; row <= sheet.RowCount; row++)
{
    string product = sheet[$"A{row}"].StringValue;
    string priceText = sheet[$"B{row}"].StringValue;
    // Convert European format to decimal
    decimal price = decimal.Parse(priceText.Replace(',', '.'));
    Console.WriteLine($"{product}: €{price}");
}

Imports System
Imports System.IO
Imports IronXL

' European CSV format (semicolon delimiter, comma decimal)
Dim europeanCsv As String = "Product;Price;Quantity" & Environment.NewLine & "Widget A;12,50;100" & Environment.NewLine & "Gadget B;24,99;50"
File.WriteAllText("european.csv", europeanCsv)

' Load with semicolon delimiter
Dim workbook As WorkBook = WorkBook.LoadCSV("european.csv", fileFormat:=ExcelFileFormat.XLSX, listDelimiter:=";")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet

' Parse European number format
For row As Integer = 1 To sheet.RowCount
    Dim product As String = sheet($"A{row}").StringValue
    Dim priceText As String = sheet($"B{row}").StringValue
    ' Convert European format to decimal
    Dim price As Decimal = Decimal.Parse(priceText.Replace(","c, "."c))
    Console.WriteLine($"{product}: €{price}")
Next row

WorkBook workbook = WorkBook.LoadCSV("large_dataset.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Process in batches of 1000 rows
int batchSize = 1000;
int totalRows = sheet.RowCount;
for (int startRow = 1; startRow <= totalRows; startRow += batchSize)
{
    int endRow = Math.Min(startRow + batchSize - 1, totalRows);
    // Process current batch
    var batchResults = new List<ProcessedRecord>();
    for (int row = startRow; row <= endRow; row++)
    {
        string id = sheet[$"A{row}"].StringValue;
        decimal amount = sheet[$"B{row}"].DecimalValue;
        // Process and store results
        batchResults.Add(new ProcessedRecord 
        { 
            Id = id, 
            Amount = amount,
            Processed = DateTime.Now 
        });
    }
    // Save batch results (to database, file, etc.)
    SaveBatch(batchResults);
    Console.WriteLine($"Processed rows {startRow} to {endRow}");
}
void SaveBatch(List<ProcessedRecord> records)
{
    // Implement batch saving logic
    Console.WriteLine($"Saved {records.Count} records");
}
class ProcessedRecord
{
    public string Id { get; set; }
    public decimal Amount { get; set; }
    public DateTime Processed { get; set; }
}

Imports System

Dim workbook As WorkBook = WorkBook.LoadCSV("large_dataset.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Process in batches of 1000 rows
Dim batchSize As Integer = 1000
Dim totalRows As Integer = sheet.RowCount
For startRow As Integer = 1 To totalRows Step batchSize
    Dim endRow As Integer = Math.Min(startRow + batchSize - 1, totalRows)
    ' Process current batch
    Dim batchResults As New List(Of ProcessedRecord)()
    For row As Integer = startRow To endRow
        Dim id As String = sheet($"A{row}").StringValue
        Dim amount As Decimal = sheet($"B{row}").DecimalValue
        ' Process and store results
        batchResults.Add(New ProcessedRecord With {
            .Id = id,
            .Amount = amount,
            .Processed = DateTime.Now
        })
    Next
    ' Save batch results (to database, file, etc.)
    SaveBatch(batchResults)
    Console.WriteLine($"Processed rows {startRow} to {endRow}")
Next

Sub SaveBatch(records As List(Of ProcessedRecord))
    ' Implement batch saving logic
    Console.WriteLine($"Saved {records.Count} records")
End Sub

Class ProcessedRecord
    Public Property Id As String
    Public Property Amount As Decimal
    Public Property Processed As DateTime
End Class

// Alternative approach using row-by-row processing
public static void ProcessLargeCsvEfficiently(string filePath)
{
    WorkBook workbook = WorkBook.LoadCSV(filePath);
    WorkSheet sheet = workbook.DefaultWorkSheet;
    // Use LINQ for memory-efficient processing
    var results = Enumerable.Range(1, sheet.RowCount)
        .Select(row => new
        {
            Row = row,
            Value = sheet[$"A{row}"].DecimalValue
        })
        .Where(item => item.Value > 100) // Filter criteria
        .Take(10000); // Limit results
    // Process results as they're enumerated
    foreach (var item in results)
    {
        Console.WriteLine($"Row {item.Row}: {item.Value}");
    }
}

Imports System
Imports System.Linq
Imports IronXL

Public Module CsvProcessor
    Public Sub ProcessLargeCsvEfficiently(filePath As String)
        Dim workbook As WorkBook = WorkBook.LoadCSV(filePath)
        Dim sheet As WorkSheet = workbook.DefaultWorkSheet
        ' Use LINQ for memory-efficient processing
        Dim results = Enumerable.Range(1, sheet.RowCount) _
            .Select(Function(row) New With {
                .Row = row,
                .Value = sheet($"A{row}").DecimalValue
            }) _
            .Where(Function(item) item.Value > 100) _ ' Filter criteria
            .Take(10000) ' Limit results
        ' Process results as they're enumerated
        For Each item In results
            Console.WriteLine($"Row {item.Row}: {item.Value}")
        Next
    End Sub
End Module

// Load CSV file
WorkBook workbook = WorkBook.LoadCSV("sales_report.csv");
WorkSheet sheet = workbook.DefaultWorkSheet;
// Apply formatting to enhance readability
// Format header row
for (int col = 0; col < sheet.ColumnCount; col++)
{
    var headerCell = sheet.GetCellAt(0, col);
    headerCell.Style.Font.Bold = true;
    headerCell.Style.BackgroundColor = "#4472C4";
    headerCell.Style.Font.Color = "#FFFFFF";
}
// Format currency columns
for (int row = 1; row <= sheet.RowCount; row++)
{
    var priceCell = sheet[$"C{row}"];
    priceCell.FormatString = "$#,##0.00";
    var quantityCell = sheet[$"D{row}"];
    quantityCell.Style.HorizontalAlignment = HorizontalAlignment.Right;
}
// Auto-fit columns for better display
for (int col = 0; col < sheet.ColumnCount; col++)
{
    sheet.AutoSizeColumn(col);
}
// Save as Excel file with formatting preserved
workbook.SaveAs("formatted_report.xlsx");
Console.WriteLine("CSV converted to formatted Excel file");

Imports IronXL

' Load CSV file
Dim workbook As WorkBook = WorkBook.LoadCSV("sales_report.csv")
Dim sheet As WorkSheet = workbook.DefaultWorkSheet
' Apply formatting to enhance readability
' Format header row
For col As Integer = 0 To sheet.ColumnCount - 1
    Dim headerCell = sheet.GetCellAt(0, col)
    headerCell.Style.Font.Bold = True
    headerCell.Style.BackgroundColor = "#4472C4"
    headerCell.Style.Font.Color = "#FFFFFF"
Next
' Format currency columns
For row As Integer = 1 To sheet.RowCount
    Dim priceCell = sheet($"C{row}")
    priceCell.FormatString = "$#,##0.00"
    Dim quantityCell = sheet($"D{row}")
    quantityCell.Style.HorizontalAlignment = HorizontalAlignment.Right
Next
' Auto-fit columns for better display
For col As Integer = 0 To sheet.ColumnCount - 1
    sheet.AutoSizeColumn(col)
Next
' Save as Excel file with formatting preserved
workbook.SaveAs("formatted_report.xlsx")
Console.WriteLine("CSV converted to formatted Excel file")