Finding the Average in DataGridView columns

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

       Dim dt As DataTable

       'Now set the file type
       OpenFileDialog1.FileName = ""
       OpenFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*"
       'Set the starting directory and the title.
       OpenFileDialog1.InitialDirectory = "C:"
       OpenFileDialog1.Title = "Select a text file"

       'Present to the user.
       If OpenFileDialog1.ShowDialog() = DialogResult.OK Then

           Dim _lstErrors As New List(Of String)()
           dt = DataSetGet(OpenFileDialog1.FileName, "/t", _lstErrors)

           If dt.Rows.Count = 0 Then
               MessageBox.Show("Please use a tab delimited text file to load the details", "Warning!", MessageBoxButtons.OK, MessageBoxIcon.Warning)
           Else
               DataGridView1.AutoGenerateColumns = True
               DataGridView1.DataSource = dt
               DataGridView1.Visible = True

               'now if there are rows loop through to fine the average
               Dim iSprsTotal As Decimal = 0
               Dim iSprsColumnIndex = 1

               If (DataGridView1.Rows.Count) Then
                   For Each objDataRow As DataRow In DataGridView1.Rows
                       iSprsTotal &= Convert.ToDecimal(objDataRow(iSprsColumnIndex))
                   Next
               End If

               'now display the average
               txtAverage.Text = iSprsTotal / DataGridView1.Rows.Count

           End If
       End If
   End Sub

   Public Shared Function DataSetGet(filename As String, separatorChar As String, errors As List(Of String)) As DataTable

       errors = New List(Of String)()
       Dim table = New DataTable("Details")
       Using sr = New StreamReader(filename, Encoding.[Default])
           Dim line As String
           Dim i As Integer = 0
           While sr.Peek() >= 0
               Try
                   line = sr.ReadLine()
                   If String.IsNullOrEmpty(line) Then
                       Continue While
                   End If
                   Dim values As String() = line.Split(New Char() {ControlChars.Tab})

                   'if the is only one column here we can take that the file is in the wrong format.
                   If values.Length <= 2 Then
                       Return table
                   Else
                       Dim row = table.NewRow()
                       For colNum = 0 To values.Length - 1
                           Dim value As String = values(colNum)
                           If i = 0 Then
                               table.Columns.Add(value, GetType([String]))
                           Else
                               row(table.Columns(colNum)) = value
                           End If
                       Next
                       If i <> 0 Then
                           table.Rows.Add(row)
                       End If

                   End If
               Catch ex As Exception
                   errors.Add(ex.Message)
               End Try
               i += 1
           End While
       End Using
       Return table
   End Function