How To Read CSV File In ASP.NET With Example C# and VB.NET

Nikunj Satasiya
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Article

Introduction

NOTE
For source code, you can download it from codingvila.com or you can mail info.codingvila@gmail.com.

In this article, I'll show you, with an example, a way to upload, read/browse and show CSV file (Text File) information in ASP.NET GridView using C# and VB.NET.

CSV file is a computer file that contains Comma Separated (Comma Delimited) Values. The information from a CSV file is browsed and then once the values are separated, a DataTable is created which is able to populate the ASP.NET GridView control. If you want to export datatable to CSV file you can read this article, i not re-posting the same article on c# corner to avoid duplicate content.

HTML Markup

The following HTML Markup consists of an associate ASP.NET FileUpload control, a Button, and a GridView.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CS.aspx.cs" Inherits="CS" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <style type="text/css">
        body
        {
            font-family: Arial;
            font-size: 10pt;
        }
        table
        {
            border: 1px solid #ccc;
            border-collapse: collapse;
            background-color: #fff;
        }
        table th
        {
            background-color: #ff7f00;
            color: #fff;
            font-weight: bold;
        }
        table th, table td
        {
            padding: 5px;
            border: 1px solid #ccc;
        }
        table, table table td
        {
            border: 0px solid #ccc;
        }
        .button {
    background-color: #0094ff; /* Blue */
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 16px;
}
    </style>
</head>
<body>
    <form id="form1" runat="server">
    <asp:FileUpload ID="FileUpload1"  CssClass="button"  runat="server" />
    <asp:Button ID="btnImport" CssClass="button" runat="server" Text="Import" OnClick="ImportCSV" />
    <hr />
    <asp:GridView ID="GridView1" runat="server">
    </asp:GridView>
    </form>
</body>
</html>

Namespaces

For reading the text from CSV file, you need to import the following namespace.

using System.IO;
using System.Data;

VB.Net

Imports System.IO
Imports System.Data

Upload, Read/browse and show CSV file (Text file) information in ASP.Net GridView

When the Import button is clicked, the CSV file is first uploaded and then saved within a folder named Files. The CSV file information is browsed into a String variable using the File class ReadAllText method.

A DataTable is formed with columns same as that of the destination database table so the CSV file information is split using the new line (\n) and Comma (,) characters. Employing a loop, the information is saved into the DataTable.

Finally, the DataTable is certain to the GridView control.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Data;

public partial class CS : System.Web.UI.Page
{
    protected void ImportCSV(object sender, EventArgs e)
    {
        //Upload and save the file
        string csvPath = Server.MapPath("~/Files/") + Path.GetFileName(FileUpload1.PostedFile.FileName);
        FileUpload1.SaveAs(csvPath);

        //Create a DataTable.
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[5] { new DataColumn("Id", typeof(int)),
        new DataColumn("Name", typeof(string)),
        new DataColumn("Technology", typeof(string)),
        new DataColumn("Company", typeof(string)),
        new DataColumn("Country",typeof(string)) });

        //Read the contents of CSV file.
        string csvData = File.ReadAllText(csvPath);

        //Execute a loop over the rows.
        foreach (string row in csvData.Split('\n'))
        {
            if (!string.IsNullOrEmpty(row))
            {
                dt.Rows.Add();
                int i = 0;

                //Execute a loop over the columns.
                foreach (string cell in row.Split(','))
                {
                    dt.Rows[dt.Rows.Count - 1][i] = cell;
                    i++;
                }
            }
        }

        //Bind the DataTable.
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

VB.Net

Imports System.IO
Imports System.Data

Partial Class VB
    Inherits System.Web.UI.Page
    Protected Sub ImportCSV(sender As Object, e As EventArgs)
        'Upload and save the file
        Dim csvPath As String = Server.MapPath("~/Files/") + Path.GetFileName(FileUpload1.PostedFile.FileName)
        FileUpload1.SaveAs(csvPath)

        'Create a DataTable.
        Dim dt As New DataTable()
        dt.Columns.AddRange(New DataColumn(4) {New DataColumn("Id", GetType(Integer)), New DataColumn("Name", GetType(String)), New DataColumn("Technology", GetType(String)), New DataColumn("Company", GetType(String)), New DataColumn("Country", GetType(String))})

        'Read the contents of CSV file.
        Dim csvData As String = File.ReadAllText(csvPath)

        'Execute a loop over the rows.
        For Each row As String In csvData.Split(ControlChars.Lf)
            If Not String.IsNullOrEmpty(row) Then
                dt.Rows.Add()
                Dim i As Integer = 0

                'Execute a loop over the columns.
                For Each cell As String In row.Split(","c)
                    dt.Rows(dt.Rows.Count - 1)(i) = cell
                    i += 1
                Next
            End If
        Next

        'Bind the DataTable.
        GridView1.DataSource = dt
        GridView1.DataBind()
    End Sub
End Class

Screenshots

CSV File

Output

Summary

CSV file is a computer file that contains Comma Separated (Comma Delimited) values. The information from a CSV file is scanned and then, separating the values, a DataTable is created which is able to be accustomed populate the ASP.Net GridView control.

Reference Link