Upload a CSV file into a Gridview

You have a CSV file and you would like to display it in 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:

Drop a FileUpload control on your canvas as well as a Button for submitting the file and a Gridview control.

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.
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

Take notice that above I skipped the first row of my file. That is because our CSV's had column names as the first row... DO NOT DO THIS
unless you need to skip the row for a reason.

And that is it! Simple but useful and I hope this helps someone!