How to read a CSV file into a .NET Datatable

Question

How can I load a CSV file into a System.Data.DataTable, creating the datatable based on the CSV file?

Does the regular ADO.net functionality allow this?

Answer 1

public class Csv
{
    public static DataTable DataSetGet(string filename, string separatorChar, out List<string> errors)
    {
        errors = new List<string>();
        var table = new DataTable("StringLocalization");
        using (var sr = new StreamReader(filename, Encoding.Default))
        {
            string line;
            var i = 0;
            while (sr.Peek() >= 0)
            {
                try
                {
                    line = sr.ReadLine();
                    if (string.IsNullOrEmpty(line)) continue;
                    var values = line.Split(new[] {separatorChar}, StringSplitOptions.None);
                    var row = table.NewRow();
                    for (var colNum = 0; colNum < values.Length; colNum++)
                    {
                        var value = values[colNum];
                        if (i == 0)
                        {
                            table.Columns.Add(value, typeof (String));
                        }
                        else
                        {
                            row[table.Columns[colNum]] = value;
                        }
                    }
                    if (i != 0) table.Rows.Add(row);
                }
                catch(Exception ex)
                {
                    errors.Add(ex.Message);
                }
                i++;
            }
        }
        return table;
    }
}

Answer 2

I have been using OleDb provider. However, it has problems if you are reading in rows that have numeric values but you want them treated as text. However, you can get around that issue by creating a schema.ini file. Here is my method I used:

// using System.Data;
// using System.Data.OleDb;
// using System.Globalization;
// using System.IO;

static DataTable GetDataTableFromCsv(string path, bool isFirstRowHeader)
{
    string header = isFirstRowHeader ? "Yes" : "No";

    string pathOnly = Path.GetDirectoryName(path);
    string fileName = Path.GetFileName(path);

    string sql = @"SELECT * FROM [" + fileName + "]";

    using(OleDbConnection connection = new OleDbConnection(
              @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + pathOnly + 
              ";Extended Properties=\"Text;HDR=" + header + "\""))
    using(OleDbCommand command = new OleDbCommand(sql, connection))
    using(OleDbDataAdapter adapter = new OleDbDataAdapter(command))
    {
        DataTable dataTable = new DataTable();
        dataTable.Locale = CultureInfo.CurrentCulture;
        adapter.Fill(dataTable);
        return dataTable;
    }
}

Answer 3

Here's a solution that uses ADO.Net's ODBC text driver:

Dim csvFileFolder As String = "C:\YourFileFolder"
Dim csvFileName As String = "YourFile.csv"

'Note that the folder is specified in the connection string,
'not the file. That's specified in the SELECT query, later.
Dim connString As String = "Driver={Microsoft Text Driver (*.txt; *.csv)};Dbq=" _
    & csvFileFolder & ";Extended Properties=""Text;HDR=No;FMT=Delimited"""
Dim conn As New Odbc.OdbcConnection(connString)

'Open a data adapter, specifying the file name to load
Dim da As New Odbc.OdbcDataAdapter("SELECT * FROM [" & csvFileName & "]", conn)
'Then fill a data table, which can be bound to a grid
Dim dt As New DataTableda.Fill(dt)

grdCSVData.DataSource = dt

Once filled, you can value properties of the datatable, like ColumnName, to make utilize all the powers of the ADO.Net data objects.

In VS2008 you can use Linq to achieve the same effect.

NOTE: This may be a duplicate of this SO question.

Answer 4

With Cinchoo ETL - an open source library, you can easily convert CSV file to DataTable with few lines of code.

using (var p = new ChoCSVReader(** YOUR CSV FILE **)
     .WithFirstLineHeader()
    )
{
    var dt = p.AsDataTable();
}

For more information, please visit codeproject article.

Hope it helps.

Answer 5

Here's an excellent class that will copy CSV data into a datatable using the structure of the data to create the DataTable:

A portable and efficient generic parser for flat files

It's easy to configure and easy to use. I urge you to take a look.

Answer 6

I came across this piece of code that uses Linq and regex to parse a CSV file. The refering article is now over a year and a half old, but have not come across a neater way to parse a CSV using Linq (and regex) than this. The caveat is the regex applied here is for comma delimited files (will detect commas inside quotes!) and that it may not take well to headers, but there is a way to overcome these). Take a peak:

Dim lines As String() = System.IO.File.ReadAllLines(strCustomerFile)
Dim pattern As String = ",(?=(?:[^""]*""[^""]*"")*(?![^""]*""))"
Dim r As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex(pattern)
Dim custs = From line In lines _
            Let data = r.Split(line) _
                Select New With {.custnmbr = data(0), _
                                 .custname = data(1)}
For Each cust In custs
    strCUSTNMBR = Replace(cust.custnmbr, Chr(34), "")
    strCUSTNAME = Replace(cust.custname, Chr(34), "")
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