Summary of the method of reading CSV files in C#

Preface

CSV (Comma-Separated Values) file is a simple text file format used to store tabular data. In C#, there are several ways to read CSV files. This article will introduce several common ways to read CSV files, including using classes in the namespace, using the CsvHelper library, and using LINQ.

1. Use classes in the namespace

Namespaces provide basic file reading capabilities. Here is a basic example of using StreamReader to read CSV files:

using System;
using ;

class Program
{
    static void Main()
    {
        string filePath = "";
        string line;
        Encoding encoding = Encoding.UTF8; // Set file encoding method
        // Use StreamReader to read CSV files        using (StreamReader reader = new StreamReader(filePath, encoding))
        {
            while ((line = ()) != null)
            {
                (line);
            }
        }
    }
}

In this example, we use the StreamReader class to read the CSV file and set the encoding method of the file to UTF-8. You can change the encoding method according to actual needs, such as GBK, etc.

2. Process the title row and the specified column

CSV files usually contain header rows, and the following is an example of reading header rows and specified columns:

using System;
using ;

class Program
{
    static void Main()
    {
        string filePath = "";
        string line;
        Encoding encoding = Encoding.UTF8; // Set file encoding method
        // Use StreamReader to read CSV files        using (StreamReader reader = new StreamReader(filePath, encoding))
        {
            // Read the title line            var header = ();
            var headers = (',');

            // Read the specified column            while ((line = ()) != null)
            {
                var fields = (',');
                ($"{headers[0]}: {fields[0]}, {headers[1]}: {fields[1]}");
            }
        }
    }
}

In this example, we first read the header row and then use the column names in the header row to output the data for the specified column.

3. Use the CsvHelper library

CsvHelper is a popular third-party library for processing CSV files. First, you need to install the CsvHelper package in your project, which can be installed through the NuGet package manager:

Install-Package CsvHelper

Then, use CsvHelper's CsvReader class to read the CSV file:

using CsvHelper;
using ;
using System;

class Program
{
    static void Main()
    {
        string filePath = "";
        var config = new CsvConfiguration { HasHeaderRecord = true };

        // Use CsvReader to read CSV files        using (var reader = new CsvReader((filePath), config))
        {
            var records = &lt;dynamic&gt;();
            foreach (var record in records)
            {
                ($"{record.Field1}, {record.Field2}, {record.Field3}");
            }
        }
    }
}

In this example, we use the CsvReader class to read the CSV file and use the GetRecords() method to convert the records into a dynamic object.

4. Advanced features and exception handling

When using the CsvHelper library, you can take some advanced features such as data verification or exception handling. Here is an example:

using CsvHelper;
using ;
using System;

class Program
{
    static void Main()
    {
        string filePath = "";
        var config = new CsvConfiguration { HasHeaderRecord = true };
          // Use CsvReader to read CSV files        using (var reader = new CsvReader((filePath), config))
        {
            ();
            // Verify the title line            if ((header =&gt; header == "InvalidField"))
            {
                throw new InvalidDataException("The CSV file contains invalid fields.");
            }

            var records = &lt;dynamic&gt;();
            foreach (var record in records)
            {
                // Verify record                if (record.Field1 == "InvalidValue")
                {
                    throw new InvalidDataException("The CSV file contains invalid values.");
                }
                ($"{record.Field1}, {record.Field2}, {record.Field3}");
            }
        }
    }
}

In this example, we first read the title row and then verify that the fields in the title row and record contain invalid data. If invalid data is included, we will throw an exception.

5. Use LINQ

LINQ (Language Integrated Query) provides a concise way to query data. Here is an example of using LINQ to read a CSV file:

using System;
using ;
using ;

class Program
{
    static void Main()
    {
        string filePath = "";
        string[] lines = (filePath);

        foreach (var line in lines)
        {
            string[] fields = (',');
            ($"{fields[0]}, {fields[1]}, {fields[2]}");
        }
    }
}

In this example, we use the () method to read all lines of the CSV file, and then use the Split() method to split the fields of each line and output them to the console.

6. Summary

In C#, there are several ways to read CSV files, including using classes in namespace, using CsvHelper library, and using LINQ. You can choose the most suitable method according to the specific needs and scenarios. Hope this article helps you better understand and use these methods.

In practical applications, the following points should be paid attention to when reading CSV files:

Make sure that the encoding method of the file is consistent with the encoding method in the code, otherwise it may lead to garbled code.
If the data in the CSV file contains special characters (such as commas, quotes, etc.), it may be necessary to escape.
When using third-party libraries such as CsvHelper, make sure that the corresponding package is installed and the relevant namespace is correctly referenced.
When processing CSV files, consider data verification and exception handling to ensure program stability and data accuracy.

This is the end of this article about the method of reading CSV files in C#. For more related contents of reading CSV files in C#, please search for my previous articles or continue browsing the following related articles. I hope everyone will support me in the future!