Datagridview Data Export to Excel In Vb.Net with Save File Dialog

Imports System.IO
Imports Excel = Microsoft.Office.Interop.Excel
Public Class Form1
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
                SaveFileDialog1.Filter = "Excel Documents|*.xlsx"
    End Sub
    Public Function ExcelColName(ByVal Col As Integer) As String
        If Col < 0 And Col > 256 Then
            MsgBox("Invalid Argument", MsgBoxStyle.Critical)
            Return Nothing
            Exit Function
        End If
        Dim i As Int16
        Dim r As Int16
        Dim S As String
        If Col <= 26 Then
            S = Chr(Col + 64)
        Else
            r = Col Mod 26
            i = System.Math.Floor(Col / 26)
            If r = 0 Then
                r = 26
                i = i - 1
            End If
            S = Chr(i + 64) & Chr(r + 64)
        End If
        ExcelColName = S
    End Function
    Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
        If SaveFileDialog1.ShowDialog = DialogResult.OK Then
            Dim sheetIndex As Integer
            Dim Ex As Object
            Dim Wb As Object
            Dim Ws As Object
            Ex = CreateObject("Excel.Application")
            Wb = Ex.workbooks.add
            Dim col, row As Integer
            Dim rawData(DataGridView1.Rows.Count, DataGridView1.Columns.Count - 1) As Object
            For col = 0 To DataGridView1.Columns.Count - 1
                rawData(0, col) = DataGridView1.Columns(col).HeaderText.ToUpper
            Next
            For col = 0 To DataGridView1.Columns.Count - 1
                For row = 0 To DataGridView1.Rows.Count - 1
                    rawData(row + 1, col) = DataGridView1.Rows(row).Cells(col).Value
                Next
            Next
            Dim finalColLetter As String = String.Empty
            finalColLetter = ExcelColName(DataGridView1.Columns.Count)
            sheetIndex += 1
            Ws = Wb.Worksheets(sheetIndex)
            Dim excelRange As String = String.Format("A1:{0}{1}", finalColLetter, DataGridView1.Rows.Count + 1)
            Ws.Range(excelRange, Type.Missing).Value2 = rawData
            Ws = Nothing
            Wb.SaveAs(SaveFileDialog1.FileName, Type.Missing, Type.Missing,
         Type.Missing, Type.Missing, Type.Missing, Type.Missing,
         Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing)
            Wb.Close(True, Type.Missing, Type.Missing)
            Wb = Nothing
            ' Release the Application object
            Ex.Quit()
            Ex = Nothing
            ' Collect the unreferenced objects
            GC.Collect()
            MsgBox("Exported Successfully.", MsgBoxStyle.Information)
        End If
    End Sub
End Class

Imports System.IO

Public Class Form1

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        'Save File In .txt (Notepad)
        Dim Save As New SaveFileDialog()
        Dim myStreamWriter As System.IO.StreamWriter
        Save.Filter = "Text [*.txt*]|*.txt"
        Save.CheckPathExists = True
        Save.Title = "Save File"
        Save.ShowDialog(Me)
        Try
            myStreamWriter = System.IO.File.AppendText(Save.FileName)
            myStreamWriter.Write(TextBox1.Text)
            myStreamWriter.Flush()
        Catch ex As Exception
        End Try
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
         If SaveFileDialog1.ShowDialog = DialogResult.OK Then
            System.IO.File.WriteAllText(SaveFileDialog1.FileName, TextBox1.Text)
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        SaveFileDialog1.Filter = "Word Documents|*.doc"
    End Sub
End Class