vb.net datagridview导出到excel表

Public Function ExportXLsD(ByVal datagrid As DataGrid) ', ByVal Title As String)
  'Dim Mytable As New DataTable
  'Mytable = CType(datagrid.DataSource, DataTable)
  If mytable Is Nothing Then
    MessageBox.Show("没有记录不能导出数据", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
    Exit Function
  End If
  If mytable.Rows.Count > 0 Then
    Dim MyFileName As String
    Dim FileName As String
    With SaveFileDialog1
     .AddExtension = True '如果用户忘记添加扩展名，将自动家上
     .DefaultExt = "xls" '默认扩展名
     .Filter = "Excel文件(*.xls)|*.xls"
     .Title = "文件保存到"
     If .ShowDialog = DialogResult.OK Then
     FileName = .FileName
     End If
    End With
    MyFileName = Microsoft.VisualBasic.Right(FileName, 4)
    If MyFileName = "" Then
     Exit Function
    End If
    If MyFileName = ".xls" Or MyFileName = ".XLS" Then
     Dim FS As FileStream = New FileStream(FileName, FileMode.Create)
     Dim sw As StreamWriter = New StreamWriter(FS, System.Text.Encoding.Default)
     sw.WriteLine(vbTab & FileName & vbTab & Date.Now)
     Dim i, j As Integer
     Dim str As String = ""
     For i = 0 To mytable.Columns.Count - 1
     str = mytable.Columns(i).Caption
     sw.Write(str & vbTab)
     Next
     sw.Write(vbCrLf)
     For j = 0 To mytable.Rows.Count - 1
     For i = 0 To mytable.Columns.Count - 1
      Dim strColName, strRow As String
      strRow = IIf(mytable.Rows(j).Item(i) Is DBNull.Value, "", mytable.Rows(j).Item(i))
      sw.Write(strRow & vbTab)
     Next
     sw.Write(vbLf)
     Next
     sw.Close()
     FS.Close()
     MessageBox.Show("数据导出成功！", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
    Else
     Exit Function
    End If
  Else
    MessageBox.Show("没有记录不能导出数据", "PurpleStar", MessageBoxButtons.OK, MessageBoxIcon.Information)
  End If
  End Function
  Private Sub OK_Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK_Button.Click
  Dim saveExcel As SaveFileDialog
  saveExcel = New SaveFileDialog
  saveExcel.Filter = "Excel文件(.xls)|*.xls"
  Dim filename As String
  If saveExcel.ShowDialog = Windows.Forms.DialogResult.Cancel Then Exit Sub
  filename = saveExcel.FileName
  Dim excel As Excel.Application
  excel = New Excel.Application
  excel.DisplayAlerts = False
  excel.Workbooks.Add(True)
  excel.Visible = False
  Dim i As Integer
  For i = 0 To DataGridView1.Columns.Count - 1
    excel.Cells(1, i + 1) = DataGridView1.Columns(i).HeaderText
  Next
  '设置标题
  Dim j As Integer
  For i = 0 To DataGridView1.Rows.Count - 1 '填充数据
    For j = 0 To DataGridView1.Columns.Count - 1
     excel.Cells(i + 2, j + 1) = DataGridView1(j, i).Value
    Next
  Next
  excel.Workbooks(1).SaveCopyAs(filename) '保存
  Me.Close()
  End Sub