Uploading and Deleting Files via Form in ASP.NET and VB

This tutorial will show how we can upload files to a web server and also use a GridView control to delete files as well. VB version.

Quite often, we want to allow uploading of files to a web server, which enables new content to be loaded much quicker & easier than using FTP. ASP.NET makes this easy for us to do, but what happens when we want to delete files from a web server, too? Well ASP.NET, of course, has an answer for this too. We can use a GridView to display files in a certain directory, and allow a user to delete these files.
First, we need the following assembly reference:

Imports System.IO

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We need to add a FileUpload control and a GridView:

<form id="form1" runat="server"> <asp:Label ID="labelStatus" runat="server"></asp:Label><br /> <asp:FileUpload ID="FileUpload1" runat="server" /><br /> <asp:Button ID="Button1" runat="server" Text="Upload" OnClick="Button1_Click" /><br /><br /> <asp:GridView ID="GridView1" runat="server" DataSource="<%# GetUploadList() %>" OnRowDeleting="GridView1_RowDeleting" AutoGenerateColumns="False" > <Columns> <asp:TemplateField HeaderText="Uploaded File"> <ItemStyle HorizontalAlign="Center" Width="70%" /> <ItemTemplate> <asp:HyperLink ID="FileLink" NavigateUrl='<%# "media/ul/" + Container.DataItem.ToString() %>' Text='<%# Container.DataItem.ToString() %>' runat="server" Target="_blank" /> </ItemTemplate> </asp:TemplateField> <asp:TemplateField HeaderText="Delete?"> <ItemStyle HorizontalAlign="Center" Width="30%" /> <ItemTemplate> <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Delete" OnClientClick='return confirm("Are you sure you want to delete this entry?");' Text="Delete?" /> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </form>

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The code-behind will look something like this:

Imports System.IO Partial Class _Default Inherits System.Web.UI.Page Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load End Sub Protected Overrides Sub OnLoad(ByVal e As System.EventArgs) MyBase.OnLoad(e) If (Not IsPostBack) Then GridView1.DataBind() End If End Sub Protected Function GetUploadList() As String() Dim folder As String = Server.mapPath("/media/ul") Dim files() As String = Directory.GetFiles(folder) Dim fileNames(files.Length - 1) As String Array.Sort(files) For i As Integer = 0 To files.Length - 1 fileNames(i) = Path.GetFileName(files(i)) Next i Return fileNames End Function Protected Sub UploadThisFile(ByVal upload As FileUpload) If upload.HasFile Then Dim theFileName As String = Path.Combine(Server.mapPath("/media/ul"), upload.FileName) upload.SaveAs(theFileName) labelStatus.Text = "<b>File has been uploaded.</b>" End If End Sub Protected Sub GridView1_RowDeleting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewDeleteEventArgs) Handles GridView1.RowDeleting e.Cancel = True Dim fileName As String = (CType(GridView1.Rows(e.RowIndex).FindControl("FileLink"), HyperLink)).Text fileName = Path.Combine(Server.MapPath("/media/ul"), fileName) File.Delete(fileName) GridView1.DataBind() End Sub Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click UploadThisFile(FileUpload1) GridView1.DataBind() End Sub End Class

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