How to Upload Files in ASP.NET using VB.NET

ASP.NET 4.0 comes with a FileUpload control that allows you to send a file from your computer to a Web server. The file to be uploaded is submitted to the server as part of the browser request during postback. After the file has completed uploading, you can manage the file in your code.

1. Create an ASP.NET project in Visual Studio 2010.

2. Drag and drop a FileUpload control on Web Form.

3. Write this code on the Page Load event of the Web Form. You need to make sure your folder on the Web Server is set to a valid directory and have write permissions on it.

Protected Sub Page_Load(ByVal sender As Object,
        ByVal e As System.EventArgs) Handles Me.Load
    If IsPostBack Then
        Dim path As String = Server.MapPath("~/UploadFilesFolder/")
        Dim fileOK As Boolean = False
        If FileUpload1.HasFile Then
            Dim fileExtension As String
            fileExtension = System.IO.Path. _
                GetExtension(FileUpload1.FileName).ToLower()
            Dim allowedExtensions As String() = _
                {".jpg", ".jpeg", ".png", ".gif"}
            For i As Integer = 0 To allowedExtensions.Length - 1
                If fileExtension = allowedExtensions(i) Then
                   fileOK = True
                End If
            Next
            If fileOK Then
                Try
                    FileUpload1.PostedFile.SaveAs(path & _
                         FileUpload1.FileName)
                    Label1.Text = "File uploaded!"
                Catch ex As Exception
                    Label1.Text = "File could not be uploaded."
                End Try
            Else
                Label1.Text = "Cannot accept files of this type."
            End If
        End If
    End If
End Sub