Upload a CSV file into a Gridview

This bit of code was born out of a desire to allow user's to see their CSV contents inside of a Gridview.  Once the user had a chance to see it they could click a button to move to the next step.

This following code will take the CSV and turn it into a dataTable that will be able then bound to a Gridview.  This makes it easy to further manipulate your data or even saving the dataTable to session for future use.

THE CODE:

1. Drop a FileUpload control on your canvas as well as a Button for submitting the file and a Gridview control.
2. Then add the System.IO, your Variables, and the Click Event to the Button.
   
   Imports System.IO

   Partial Public Class _Default
       Inherits System.Web.UI.Page

       Dim streamRdr As StreamReader
       Dim fileLines As String()
       Dim line As String

       Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

           If FileUpload1.HasFile Then

               Dim fileExt As String

               fileExt = System.IO.Path.GetExtension(FileUpload1.FileName)

               If fileExt = ".csv" Or fileExt = ".CSV" Then

                   'Make variables needed
                   Dim objStream As Stream
                   Dim fileLen As Integer

                   'Get the length of the file.
                   fileLen = FileUpload1.PostedFile.ContentLength

                   'Create a byte array to hold the contents of the file.
                   Dim Input(fileLen) As Byte

                   'Move byte array into a stream, then start it at beginning and pass it to method.
                   objStream = FileUpload1.PostedFile.InputStream
                   objStream.Read(Input, 0, fileLen)
                   objStream.Position = 0

                   'Manage File
                   importToDG(objStream)

               End If

           End If

       End Sub

    NOTICE above, we verify that we are getting a CSV file in and then we create a stream to hold the incoming file.
   
   We then get the length, create a byte array to temporarily hold the contents, move it into the stream, then reset the stream's position.
   
   Finally we call our next method 'importToDG' and send in the stream.

3. Create the import Sub - you will need to create a Datatable, a row, and the columns that match your CSV. You need to put your CSV info into a datatable for the Gridview can bind to it.
   
   Private Sub importToDG(ByVal fileStream As Stream)

       streamRdr = New StreamReader(FileStream)

       Dim myDTable As DataTable = New DataTable
       Dim myDRow As DataRow = myDTable.NewRow
       Dim schoolID, distID, schoolName, Address, Address2, Phone, City, State, Zip _
                    As New DataColumn
       schoolID.ColumnName = "SchoolID"
       distID.ColumnName = "DistrictID"
       Phone.ColumnName = "Phone"
       schoolName.ColumnName = "schoolName"
       Address.ColumnName = "Address"
       Address2.ColumnName = "Address2"
       City.ColumnName = "City"
       State.ColumnName = "State"
       Zip.ColumnName = "Zip"
       myDTable.Columns.Add(schoolID)
       myDTable.Columns.Add(distID)
       myDTable.Columns.Add(schoolName)
       myDTable.Columns.Add(Address)
       myDTable.Columns.Add(Address2)
       myDTable.Columns.Add(Phone)
       myDTable.Columns.Add(City)
       myDTable.Columns.Add(State)
       myDTable.Columns.Add(Zip)

       'Now set the streamreader back to beginning.
       streamRdr.DiscardBufferedData()
       streamRdr.BaseStream.Seek(0, SeekOrigin.Begin)
       streamRdr.BaseStream.Position = 0

       Dim i As Integer = 0 'Skip the first row.

       While Not streamRdr.EndOfStream

           line = streamRdr.ReadLine 'Read first line
           fileLines = line.Split(",") 'Split the line up by the delimeter

           If i > 0 Then
               myDRow.ItemArray = fileLines
               myDTable.Rows.Add(myDRow)
               myDRow = myDTable.NewRow
           End If

           i += 1

       End While

       GridView1.DataSource = myDTable
       GridView1.DataBind()

   End Sub

   End Class