In this article I will explain with an example, how to display list of files from Folder (Directory) in ASP.Net using C# and VB.Net.
 
 

Files Folder (Directory) Location

The files are located inside the Files Folder (Directory) of ASP.Net project.
Display List of Files from Folder (Directory) in ASP.Net
 
 

HTML Markup

The HTML Markup consists of following control:
GridView – For displaying data.

Columns

The GridView consists of a BoundField column and a TemplateField column.
The TemplateField consists of an ItemTemplate inside which a LinkButton is used.
The LinkButton has been assigned with following property:
CommandArgument – It is set with the path of the file.
The LinkButton has been assigned with the OnClick event handler.
<asp:GridView ID="gvFiles" runat="server" AutoGenerateColumns="false" EmptyDataText="No files uploaded"> 
    <Columns>
        <asp:BoundField DataField="Text" HeaderText="File Name" />
        <asp:TemplateField>
            <ItemTemplate>
                <asp:LinkButton ID="lnkDownload" Text="Download" CommandArgument='<%# Eval("Value" )%>' runat="server" OnClick="DownloadFile"></asp:LinkButton> 
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>
 
 

Namespaces

You will need to import the following namespaces.
C#
using System.IO;
using System.Web;
 
VB.Net
Imports System.IO
Imports System.Web
 
 

Displaying List of Files from Folder (Directory)

Inside the Page_Load event handler, the path of all files in the Files Folder (Directory) is fetched using the GetFiles method of the Directory class and stored into a String Array.
Then, a Generic List collection of ListItem class object is created.
After that, a FOR EACH loop is executed over the path of the files and the file name and file path is stored into a new ListItem class object as Text and Value respectively.
Finally, the Generic List collection of ListItem class object is assigned to the DataSource property of the GridView and the GridView is populated.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        //Fetch all files in the Folder (Directory).
        string[] filePaths = Directory.GetFiles(Server.MapPath("~/Files/"));
        List<ListItem> files = new List<ListItem>();
 
        //Populating Listof ListItem  class.
        foreach (string filePath in filePaths)
        {
            //Storing the Name and Path in Text and Value properties.
            files.Add(new ListItem()
            {
                 Text = Path.GetFileName(filePath),
                 Value = filePath
            });
        }
 
        gvFiles.DataSource = files;
        gvFiles.DataBind();
    }
}
 
VB.Net
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        'Fetch all files in the Folder (Directory).
        Dim filePaths() As String = Directory.GetFiles(Server.MapPath("~/Files/"))
        Dim files As List(Of ListItem) = New List(Of ListItem)
 
        'Populating Listof ListItem  class.
        For Each filePath As String In filePaths
            'Storing the Name and Path in Text and Value properties.
            files.Add(New ListItem() With {
            .Text = Path.GetFileName(filePath),
            .Value = filePath
        })
        Next
        gvFiles.DataSource = files
        gvFiles.DataBind()
    End If
End Sub
 
 

Downloading Files using C# and VB.Net

When the Download LinkButton is clicked, the file path and the file name of the associated file are determined.
Then, the Response class properties are set.
Properties:
1. ContentType – It informs the Browser about the file type.
The file is determined using GetMimeMapping method of MimeMapping class.
Note: For more details on MimeMapping class, please refer my article Get MIME Type (Content Type) of a File in ASP.Net.
 
2. Content-Disposition – It is a response header indicating, the download file is an attachment and allows setting the file name.
Note: For more details on Content-Disposition, please refer my article What is Content Disposition Header in ASP.Net.
 
Finally, the file is written to the Response using WriteFile method using file path as parameter and the File is downloaded.
C#
protected void DownloadFile(object  sender,EventArgs e)
{
    //Fetch the path of the File.
    string  filePath = (senderas LinkButton).CommandArgument;
 
    //Determine the name of the File.
    string  fileName = Path.GetFileName(filePath);
 
    //Determine and set the Content Type of the File.
    Response.ContentType  = MimeMapping.GetMimeMapping(fileName);
 
    //Specifying that the file is an Attachment.
    Response.AppendHeader("Content-Disposition","attachment; filename=" + fileName);
 
    //Writing the File to theRespone.
    Response.WriteFile(filePath);
    Response.End();
}
 
VB.Net
Protected Sub DownloadFile(ByVal  sender As Object,  ByVal  e As EventArgs)
    'Fetch the path of the File.
    Dim  filePath As String  =  CType(sender,LinkButton).CommandArgument
 
    'Determine the name of the File.
    Dim  fileName As String  = Path.GetFileName(filePath)
 
    'Determine and set the Content Type of the File.
    Response.ContentType  = MimeMapping.GetMimeMapping(fileName)
 
    'Specifying that the file is an Attachment.
    Response.AppendHeader("Content-Disposition", ("attachment; filename=" + fileName))
 
    'Writing the File to theRespone.
    Response.WriteFile(filePath)
    Response.End()
End Sub
 
 

Screenshot

Display List of Files from Folder (Directory) in ASP.Net
 
 

Downloads

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