Develop Reference

Double values get converted to string values when the double values has decimal points

I am trying to use CSVHelper library to write data into a MemoryStream and then generate a CSV file using that MemoryStream.
The problem is Double values get converted to weird string values when the double values have decimal points. The expected output and weird output are there at the bottom.
Is anyone know how to overcome this issue? or Is there any mistake in the below code?
public class Foo
{
public Foo()
{
}
public double valOne { get; set; }
public double valTwo { get; set; }
}
public class FooMap : ClassMap<Foo>
{
public FooMap()
{
Map(m => m.valOne).Index(0).Name("Val One");
Map(m => m.valTwo).Index(1).Name("Val Two");
}
}
var records = new List<Foo> {
new Foo{valOne = 3224.12, valTwo = 4122},
new Foo{valOne = 2030.20, valTwo = 5555},
};
var config = new CsvConfiguration(CultureInfo.CurrentCulture) { Delimiter = ",", HasHeaderRecord = true };
using (var memoryStream = new MemoryStream())
using (var writer = new StreamWriter(memoryStream))
using (var csv = new CsvWriter(writer, config))
{
csv.Context.RegisterClassMap<FooMap>();
csv.WriteHeader<Foo>();
csv.NextRecord();
foreach (var record in records)
{
csv.WriteRecord(record);
csv.NextRecord();
}
writer.Flush();
var result = Encoding.UTF8.GetString(memoryStream.ToArray());
byte[] bytes = Encoding.ASCII.GetBytes(result);
return new FileContentResult(bytes, "text/csv")
{
FileDownloadName = "Sample_Report_Name"
};
}
Expected Output:
Val One, Val Two
3224.12,4122
2030.20,5555
Weird Output:
Val One, Val Two
"3224,12",4122
"2030,20",5555

The issue is the CurrentCulture of the computer running the code uses commas instead of periods to indicate the decimal point. Using CultureInfo.InvariantCulture instead of CultureInfo.CurrentCulture should fix the formatting issue.
Also, you can simplify your code by using csv.WriteRecords(records).
var records = new List<Foo> {
new Foo{valOne = 3224.12, valTwo = 4122},
new Foo{valOne = 2030.20, valTwo = 5555},
};
var config = new CsvConfiguration(CultureInfo.CurrentCulture) { Delimiter = ",", HasHeaderRecord = true };
using (var memoryStream = new MemoryStream())
using (var writer = new StreamWriter(memoryStream))
using (var csv = new CsvWriter(writer, config))
{
csv.Context.RegisterClassMap<FooMap>();
csv.WriteRecords(records);
writer.Flush();
var result = Encoding.UTF8.GetString(memoryStream.ToArray());
byte[] bytes = Encoding.ASCII.GetBytes(result);
return new FileContentResult(bytes, "text/csv")
{
FileDownloadName = "Sample_Report_Name"
};
}

how to access records in csv helper

The code below reads a column of a csv file.
It does that properly.
I want to copy var records to a decimal array.
I am using csv helper.
How best to do it?
using (var reader = new StreamReader(filename))
using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
{
var records = new List<Filevalues>();
csv.Read();
csv.ReadHeader();
while (csv.Read())
{
var record = new Filevalues
{
File_vals = csv.GetField<decimal>("File_vals"),
};
records.Add(record);
}
}
public class Filevalues
{
public decimal File_vals{ get; set; }
}

At its most simple:
using var csv = new CsvReader(new StreamReader(filename), CultureInfo.InvariantCulture));
csv.GetRecords<Filevalues>().Select(f => f.File_vals).ToArray();
(I think I'd ToList() it instead of array, and work with the List)
If the CSV is so simple that it's just a list of decimals, I might skip using a CSV library all together:
File.ReadLines(path).Skip(1).Select(decimal.Parse).ToArray();

Either:
using (var reader = new StreamReader(filename))
using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
{
var listOfDecimals = new List<decimal>();
csv.Read();
csv.ReadHeader();
while (csv.Read())
{
listOfDecimals.Add(csv.GetField<decimal>("File_vals"));
}
var arrayOfDecimals = listOfDecimals.ToArray();
}
ToArray: https://learn.microsoft.com/en-us/dotnet/api/system.linq.enumerable.toarray
Or:
using (var reader = new StreamReader(filename))
using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
{
var records = new List<Filevalues>();
csv.Read();
csv.ReadHeader();
while (csv.Read())
{
var record = new Filevalues
{
File_vals = csv.GetField<decimal>("File_vals"),
};
records.Add(record);
}
var arrayOfDecimals = records.Select(x => x.File_vals).ToArray();
}
public class Filevalues
{
public decimal File_vals{ get; set; }
}
LINQ Projection: https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/projection-operations

Reading a CSV file using CsvHelper

I'm a newbie. I want to get data from the CSV file-the Id and Name fields, but when I run the reading method, I get only 100 lines of an incomprehensible type: "CsvHelper.CsvReaderd__87`1[Program+Product]". I do not know how to get data from CSV, I also cannot understand where the error is.
Although the documentation says that having the same names of properties and CSV headers, you do not need to write additional configurations. However, I get the result specified above. The CSV names match the classes. Link to the documentation:https://joshclose.github.io/CsvHelper/getting-started/
reading method:
{
using (var reader = new StreamReader("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", Encoding.UTF8))
using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
{
var records = csv.GetRecords<Product>();
Console.WriteLine($"{records}");
}
}
CSV is created without problems, there are two columns with Id and Name with filled rows, there are 100 rows in total:
method for creating a csv with the Id and Name fields:
using (var writer = new StreamWriter("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", false, Encoding.UTF8))
using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
{
csv.WriteRecords(products);
}
the entire code:
using CsvHelper;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Net;
using System.Text;
using System.Xml;
public class Program
{
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public Product(int id, string name)
{
Id = id;
Name = name;
}
}
public const string PathToDoc = "C:/Users/Saint/Desktop/TaskRetail/yml.xml";
public static void Main(string[] args)
{
string url = "https://www.googleapis.com/drive/v3/files/1sSR9kWifwjIP5qFWcyxGCxN0-MoEd_oo?alt=media&key=AIzaSyBsW_sj1GCItGBK0vl8hr9zu1I1vTI1Meo";
string savePath = #"C:\Users\Saint\Desktop\TaskRetail\yml.xml";
WebClient client = new WebClient();
client.DownloadFile(url, savePath);
Research();
}
public static void Research()
{
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
var document = new XmlDocument();
document.Load(PathToDoc);
var xmlDoc = document.SelectNodes("/yml_catalog/shop/offers/offer");
var count = xmlDoc.Count;
var products = new List<Product>();
Console.WriteLine($"Offers count: {count}");
for (var i = 0; i < count; i++)
{
var element = xmlDoc.Item(i);
var id = int.Parse(element.Attributes.GetNamedItem("id").Value);
var name = element.SelectSingleNode("name").InnerText;
var product = new Product(id, name);
//Console.WriteLine($"Id: {id}, name: {name}");
products.Add(product);
using (var writer = new StreamWriter("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", false, Encoding.UTF8))
using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
{
csv.WriteRecords(products);
}
var config = new CsvConfiguration(CultureInfo.InvariantCulture) { Delimiter = ",", PrepareHeaderForMatch = header => header.Header.ToLower() };
using (var reader = new StreamReader("C:\\Users\\Saint\\Desktop\\TaskRetail\\file.csv", Encoding.UTF8))
using (var csv = new CsvReader(reader, config))
{
var records = csv.GetRecords<Product>();
foreach (var record in records)
{
Console.WriteLine($"{record.Id} {record.Name}");
}
}
}
}
}

Because GetRecords() does return an object of type IEnumerable,
you have to iterate over your records to print each one of them:
foreach(var record in records)
{
Console.WriteLine($"{record.Id} {record.Name}");
}
Furthermore you have to access each property you want to print individually.
Another option would be to override the ToString() method in your Product class.
EDIT
The initial problem wasn't the correct printing of the values but the parsing of the file as I learned from this comment:
CsvHelper.HeaderValidationException: 'Header with name 'id'[0] was not found. Header with name 'name'[0] was not found.
To tackle this problem one have to make sure that the delimiter character is set correctly. This can be enforced in the config object of the CsvHelper. Furthermore to avoid casing errors the configuration can be set to ignore the casing of the headers:
var config = new CsvConfiguration(CultureInfo.InvariantCulture)
{
Delimiter = ",", // Enforce ',' as delimiter
PrepareHeaderForMatch = header => header.Header.ToLower() // Ignore casing
};
using (var csv = new CsvReader(reader, config))
{
...
}

How to exclude header when writing data to CSV

I am writing my data from a public class to a CSV file. As I want to append my data, I want to exclude the importing of header and only import the data from the class. My code below imports both headers and data. Hope to get help. Thanks.
Record.cs - my class
public class Record
{
public string Name
{
get; set;
}
public DateTime DateOfBirth
{
get; set;
}
}
Form1.cs - my form
public partial class Form1 : Form
{
private List<Record> records;
public Form1()
{
InitializeComponent();
records = new List<Record>();
}
private void Savetocsv_Click(object sender, EventArgs e)
{
var myDocument = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
using (var writer = new StreamWriter(myDocument + "/my-data.csv", append: true))
{
using (var csv = new CsvWriter(writer))
{
csv.WriteRecords(records);
}
}
}

Using the Configuration , you can use the property HasHeaderRecord:
HasHeaderRecord :
Gets or sets a value indicating if the CSV file has a header record.
Default is true.
var records = new List<Foo>
{
new Foo { Id = 1, Name = "one" },
new Foo { Id = 1, Name = "one" },
};
using (var writer = new StreamWriter($"file.csv"))
using (var csv = new CsvWriter(writer, new Configuration { HasHeaderRecord = false }))
{
csv.WriteRecords(records);
}
Result file : "file.csv"
1;one
1;one
Or simply loop on records an write them:
var records = new List<Foo>
{
new Foo { Id = 1, Name = "one" },
new Foo { Id = 1, Name = "one" }
};
using (var writer = new StreamWriter($"file.csv"))
using (var csv = new CsvWriter(writer))
{
foreach (var record in records)
{
csv.WriteRecord(record);
csv.NextRecord();
}
}

The name of the configuration class has changed.
using (var csv = new CsvWriter(outputStream, new CsvConfiguration(CultureInfo.InvariantCulture)
{
HasHeaderRecord = false
}))

Change your writing method as following and then CsvHelper.WriterConfiguration do the trick (note HasHeaderRecord):
private void Savetocsv_Click(object sender, EventArgs e)
{
var myDocument = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
using (var writer = new StreamWriter(myDocument + "/my-data.csv", append: true))
{
using (var csv = new CsvWriter(writer, new Configuration { HasHeaderRecord = false }))
{
csv.WriteRecords(records);
}
}
}

I don't know which CsvWriter you are using, but the one here has a HasHeaderRecord property that you can use to ignore or include headers.
private void Savetocsv_Click(object sender, EventArgs e)
{
var myDocument = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
using (var writer = new StreamWriter(myDocument + "/my-data.csv", append: true))
{
using (var csv = new CsvWriter(writer))
{
csv.Configuration.HasHeaderRecord = true;
csv.WriteRecords(records);
}
}
}

Remove the first row from records before calling:
csv.WriteRecords(records);
(If you need to leave records unchanged, add the headers back again after calling WriteRecords(...).)
private void Savetocsv_Click(object sender, EventArgs e)
{
var myDocument = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
using (var writer = new StreamWriter(myDocument + "/my-data.csv", append: true))
{
using (var csv = new CsvWriter(writer))
{
records.RemoveAt(0); // Removes the header row.
csv.WriteRecords(records);
}
}
}

CSV File with cells containing commas, Reading data into C# Program

I'm writing a program to read in CSV files and validate the data. The csv file is comma delimited.
The csv file contains a sales order that is retrieved online so we can't actually edit the CSV file itself. I need to read in the file and split it into the cells. However, the product description will contain further commas which is affecting how I access the data.
My code for pulling the values out is below.
private void csvParse()
{
List<string> products = new List<string>();
List<string> quantities = new List<string>();
List<string> price = new List<string>();
using (var reader = new StreamReader(txt_filePath.Text.ToString()))
{
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
var values = line.Split(',');
products.Add(values[0]);
quantities.Add(values[2]);
values[3] = values[3].Substring(4);
price.Add(values[3]);
}
}
if (validateData(products, quantities, price) != "")
{
MessageBox.Show(validateData(products, quantities, price));
}
}
Is there anyway to ignore the columns in a set cell or can the columns distinguished by another delimiter?
A snippet of a row in my csv file is below.
The raw CSV data is below:
TO12345,"E45 Dermatological Moisturising Lotion, 500 ml",765,GBP 1.75

You can use LinqToCSV from nuGet. ie:
void Main()
{
List<MyData> sample = new List<MyData> {
new MyData {Id=1, Name="Hammer", Description="Everything looks like a nail to a hammer, doesn't it?"},
new MyData {Id=2, Name="C#", Description="A computer language."},
new MyData {Id=3, Name="Go", Description="Yet another language, from Google, cross compiles natively."},
new MyData {Id=3, Name="BlahBlah"},
};
string fileName = #"c:\temp\MyCSV.csv";
File.WriteAllText(fileName,"Id,My Product Name,Ignore1,Ignore2,Description\n");
File.AppendAllLines(fileName, sample.Select(s => $#"{s.Id},""{s.Name}"",""ignore this"",""skip this too"",""{s.Description}"""));
CsvContext cc = new CsvContext();
CsvFileDescription inputFileDescription = new CsvFileDescription
{
SeparatorChar = ',',
FirstLineHasColumnNames = true,
IgnoreUnknownColumns=true
};
IEnumerable<MyData> fromCSV = cc.Read<MyData>(fileName, inputFileDescription);
foreach (var d in fromCSV)
{
Console.WriteLine($#"ID:{d.Id},Name:""{d.Name}"",Description:""{d.Description}""");
}
}
public class MyData
{
[CsvColumn(FieldIndex = 1, Name="Id", CanBeNull = false)]
public int Id { get; set; }
[CsvColumn(FieldIndex = 2, Name="My Product Name",CanBeNull = false, OutputFormat = "C")]
public string Name { get; set; }
[CsvColumn(FieldIndex = 5, Name="Description",CanBeNull = true, OutputFormat = "C")]
public string Description { get; set; }
}

It should work..:)
var csvSplit = new Regex("(?:^|,)(\"(?:[^\"]+|\"\")*\"|[^,]*)", RegexOptions.Compiled);
string[] csvlines = File.ReadAllLines(txt_filePath.Text.ToString());
var query = csvlines.Select(csvline => new
{
data = csvSplit.Matches(csvline)
}).Select(t => t.data);
var row = query.Select(matchCollection =>
(from Match m in matchCollection select (m.Value.Contains(',')) ? m.Value.Replace(",", "") : m.Value)
.ToList()).ToList();

You can also use the Microsoft.VisualBasic.FileIO.TextFieldParser class. More detailed answer here: TextFieldParser