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

Nikunj Satasiya
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Article

Introduction

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.

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.

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