ASP.NET Upload Multiple Files using FileUpload

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ASP.NET Uploading Multiple Files using FileUpload control:

ASP.NET File upload control allows to upload multiple files at once. This feature is supported by all browsers which supports HTML5. File upload control has a property named “AllowMultiple” which accepts bool value of true or false, using which we can get all the files which are selected by the user on the front-end and save it on the server-side when submitting the form or a post back event. So let’s see how to make it work and get multiple files using File upload control in ASP.NET.

Example of uploading multiple files:

We will create two file upload control, one will accept only images and other will accept document like PDF, DOC.

Default.aspx:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="AspTutorial.Default" %>

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>ASP.NET Multi-File upload</title>
<style>

</style>
</head>
<body style="font-family:Arial, Helvetica, sans-serif">
<form id="form1" runat="server">
<div>
<h2>ASP.NET Multi file upload example:</h2>
<br />
<h4>Image Upload:</h4>
<asp:FileUpload runat="server" ID="imageUpload" AllowMultiple="true" accept="image/*"/>
<asp:Button runat="server" ID="btnImageUpload" Text="Upload Images" OnClick="btnImageUpload_Click"/>

<asp:Label runat="server" ID="lblImageNames" />

<br />
<h4>Document Upload:</h4>
<asp:FileUpload runat="server" ID="documentUpload" AllowMultiple="true" accept=".pdf,.doc,.docx"/>
<asp:Button runat="server" ID="btnDocumentUpload" Text="Upload Documents" OnClick="btnDocumentUpload_Click"/>

<asp:Label runat="server" ID="lblDocumentNames" />
</div>
</form>
</body>
</html>

Here, on both the labels, we will display a HTML link to navigate to the uploaded files by the users. Also we will rename all the files selected by the users and save it inside a folder called “UploadFiles“. Please create a folder with name “UploadFiles” in your project directory. asp-net-multiple-file-uploadOn the button click events of the respective buttons we will save the files from FileUpload control.

Default.aspx.cs:

using System;
using System.Text;
using System.Web;
using System.Web.UI;

namespace AspTutorial
{
public partial class Default : Page
{

protected void Page_Load(object sender, EventArgs e)
{

}

protected void btnImageUpload_Click(object sender, EventArgs e)
{
try
{
StringBuilder files = new StringBuilder();
if(imageUpload.HasFiles)
{
foreach(HttpPostedFile file in imageUpload.PostedFiles)
{

string fileName = "image-"+ Guid.NewGuid() + DateTime.Now.ToString("ddMMyyyyHHmmss")+ System.IO.Path.GetExtension(file.FileName);
string filePath = System.IO.Path.Combine(Server.MapPath("~/UploadFiles/"), fileName);
file.SaveAs(filePath);
files.Append("<br/><a href='/UploadFiles/"+ fileName + "'>" + fileName + "</a>");
}
}

lblImageNames.Text = files.ToString() ;
}
catch(Exception ex)
{
lblDocumentNames.Text = ex.Message.ToString();
}
}

protected void btnDocumentUpload_Click(object sender, EventArgs e)
{
try
{
StringBuilder files = new StringBuilder();
if (documentUpload.HasFiles)
{
foreach (HttpPostedFile file in documentUpload.PostedFiles)
{
string fileName = "document-" + DateTime.Now.ToString("ddMMyyyyHHmmss") + System.IO.Path.GetExtension(file.FileName);
string filePath = System.IO.Path.Combine(Server.MapPath("~/UploadFiles/"), fileName);
file.SaveAs(filePath);
files.Append("<br/><a href='/UploadFiles/" + fileName + "'>" + fileName + "</a>");
}
}

lblDocumentNames.Text = files.ToString();
}
catch (Exception ex)
{
lblDocumentNames.Text = ex.Message.ToString();
}
}
}
}

All the files will be saved in the “UploadFiles” folder and we are using DateTime string with the file name to avoid duplicate file name issue.

asp-net-multiple-selected-file-upload-01

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