如何在 C# 中读取 CSV 文件

Prerequisites

To convert data from a CSV file to an Excel file and read it in C#, we require the following tools:

1. Visual Studio: is an essential Integrated Development Environment (IDE) for working on C# .NET applications. It is the official and recommended IDE for developing C# apps, and it can be downloaded and installed from the Microsoft website. However, other IDEs that support a C# environment can also be used if preferred by the developer.

2. Create Console App: Follow the steps to create a simple Console Application.

   • Open Visual Studio and click "Create a Project".

     New Project Window

   • Choose "Console App" from the list of options available. Make sure the selected language is C#.

     Create a new Console App

   • Next, name your project whatever you want.

     Configuration

   • The next step in project configuration is selecting the .NET Framework. The latest version available is .NET 7.0, which is supported in the standard term. However, to avoid any potential errors, you can opt for the more stable version of .NET 6.0, as Microsoft provides long-term support for it. It's important to choose the appropriate version based on your specific requirements.
3. IronXL - It is the .NET Excel library that is designed to work with Excel spreadsheets. It must be installed in your C# application before using it. You can download and install the package from multiple sources:
   1. NuGet - the package manager for .NET. You can directly download IronXL from the NuGet website.
   2. Visual Studio NuGet Package Manager: Open the Package Manager by going to Tools > NuGet Package Manager > Manage Packages for Solution...
   3. Download the IronXL .NET Excel DLL zip file directly from the Iron website and add it to the Project Solution as a project reference.

Add IronXL Namespace

Once you have the prerequisites, the next step is to add the IronXL namespace on top of the source code in the main.cs file:

using IronXL;

using IronXL;

Imports IronXL

Open an Existing CSV File

IronXL provides an easy way to read CSV files in C#. First, open a CSV file for reading. It is a file type which is based on rows and columns. Here, the WorkBook class is used along with its LoadCSV method to open a CSV file. The code is as follows:

// Load the CSV file and convert it to XLSX format.
var csv = WorkBook.LoadCSV("color_srgb.csv", fileFormat: ExcelFileFormat.XLSX, ListDelimiter: ",");

// Load the CSV file and convert it to XLSX format.
var csv = WorkBook.LoadCSV("color_srgb.csv", fileFormat: ExcelFileFormat.XLSX, ListDelimiter: ",");

' Load the CSV file and convert it to XLSX format.
Dim csv = WorkBook.LoadCSV("color_srgb.csv", fileFormat:= ExcelFileFormat.XLSX, ListDelimiter:= ",")

The LoadCSV method in IronXL allows you to open a CSV file and convert it to XLSX format. This method provides options to specify the list delimiter used in the CSV file. In this example, the default delimiter, which is a comma, is used. The resulting file is opened and can be further processed using IronXL's features for reading and manipulating Excel spreadsheets.

CSV File

Get Worksheet from CSV Reader Class

In the previous step, the CSV file was opened as an Excel workbook using IronXL. Now, get the default worksheet from the workbook using the WorkSheet class. The following example demonstrates how to get the worksheet for reading CSV data:

// Retrieve the default worksheet from the loaded workbook.
WorkSheet ws = csv.DefaultWorkSheet;

// Retrieve the default worksheet from the loaded workbook.
WorkSheet ws = csv.DefaultWorkSheet;

' Retrieve the default worksheet from the loaded workbook.
Dim ws As WorkSheet = csv.DefaultWorkSheet

For more information on working with Excel worksheets, you can visit this code examples page.

Read CSV Data using C# DataTable

// Convert the worksheet data to a DataTable.
DataTable dt = ws.ToDataTable(true);

// Convert the worksheet data to a DataTable.
DataTable dt = ws.ToDataTable(true);

' Convert the worksheet data to a DataTable.
Dim dt As DataTable = ws.ToDataTable(True)

// Iterate over each row in the DataTable.
foreach (DataRow row in dt.Rows)
{
    // Iterate over each column in the current row.
    for (int i = 0; i < dt.Columns.Count; i++)
    {
        // Print each column value in the current row.
        Console.Write(row[i] + "  ");
    }
    // Move to the next line after printing all columns of the current row.
    Console.WriteLine();
}

// Iterate over each row in the DataTable.
foreach (DataRow row in dt.Rows)
{
    // Iterate over each column in the current row.
    for (int i = 0; i < dt.Columns.Count; i++)
    {
        // Print each column value in the current row.
        Console.Write(row[i] + "  ");
    }
    // Move to the next line after printing all columns of the current row.
    Console.WriteLine();
}

' Iterate over each row in the DataTable.
For Each row As DataRow In dt.Rows
	' Iterate over each column in the current row.
	For i As Integer = 0 To dt.Columns.Count - 1
		' Print each column value in the current row.
		Console.Write(row(i) & "  ")
	Next i
	' Move to the next line after printing all columns of the current row.
	Console.WriteLine()
Next row