ปุ๋มค้นหา ค้นหาได้แค่หัว Column เดียวครับช่วยที่ครับ

Imports System.IO
Imports System.Data.DataTable
Public Class Form1
    Dim table As New DataTable("table")
    Dim index As Integer
    Private dtTableGrd As DataTable

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'หัว Columns
        table.Columns.Add("ชื่อผู้ใช้บริการ", Type.GetType("System.String"))
        table.Columns.Add("เบอร์โทรศัพท์", Type.GetType("System.String"))
        table.Columns.Add("ประเภทรถ", Type.GetType("System.String"))
        table.Columns.Add("บริการที่ใช้", Type.GetType("System.String"))
        table.Columns.Add("ราคาบริการ", Type.GetType("System.String"))
        table.Columns.Add("วันที่บริการ", Type.GetType("System.String"))

        DataGridView1.DataSource = table
        dtTableGrd = table
    End Sub
    'เพื่มข้อมูลเพื่มแถว
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        table.Rows.Add(ชื่อ.Text, เบอร์.Text, รถ.Text, บริการ.Text, ราคา.Text, วันที่.Text)
        ชื่อ.Clear()
        เบอร์.Clear()
        ราคา.Clear()

        DataGridView1.DataSource = table

    End Sub
    'Save
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        On Error GoTo SaveErr
        Dim writer As New StreamWriter("C:\Memoryคาร์แคร์\SAVE\MemorySave.Txt")

        For i As Integer = 0 To DataGridView1.Rows.Count - 2 Step +1

            For j As Integer = 0 To DataGridView1.Columns.Count - 1 Step +1

                If j = DataGridView1.Columns.Count - 1 Then
                    writer.Write(vbTab & DataGridView1.Rows(i).Cells(j).Value.ToString() & vbTab & "l")

                Else
                    writer.Write(vbTab & DataGridView1.Rows(i).Cells(j).Value.ToString() & vbTab & "l")

                End If

            Next j

            writer.WriteLine("")

        Next
        writer.Close()
        MessageBox.Show("บันทึกเรียบร้อย")

SaveErr:
    End Sub
    'ออกจากโปรแกรม
    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Me.Close()
    End Sub
    'DeleteRow
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        On Error GoTo SaveErr
        Dim rowIndex = DataGridView1.CurrentCell.RowIndex
        DataGridView1.Rows.RemoveAt(RightToLeftLayout)
SaveErr:
    End Sub
    'ค้นหา (ใช้ไม่ได้ครับได้แค่ผู้บริการ)
    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        On Error GoTo SaveErr

        dtTableGrd.DefaultView.RowFilter = "(Convert(ชื่อผู้ใช้บริการ, 'System.String') LIKE '" & ST.Text & "')" & _
                                            "OR (เบอร์โทรศัพท์, 'System.String') LIKE '" & ST.Text & "')"

SaveErr:

    End Sub
    Private bitmap As Bitmap
    'ปริ้น
    Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click
        Dim height As Integer = DataGridView1.Height
        DataGridView1.Height = DataGridView1.RowCount * DataGridView1.RowTemplate.Height
        bitmap = New Bitmap(Me.DataGridView1.Width, Me.DataGridView1.Height)
        DataGridView1.DrawToBitmap(bitmap, New Rectangle(1, 1, Me.DataGridView1.Width, Me.DataGridView1.Height))
        PrintPreviewDialog1.Document = PrintDocument1
        PrintPreviewDialog1.PrintPreviewControl.Zoom = 1
        PrintPreviewDialog1.ShowDialog()
        DataGridView1.Height = height
    End Sub
    'ปริ้น
    Private Sub PrintDocument1_PrintPage(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage
        e.Graphics.DrawImage(bitmap, 1, 1)
        Dim rectPrint As RectangleF = e.PageSettings.PrintableArea
        If Me.DataGridView1.Height - rectPrint.Height > 0 Then e.HasMorePages = True
    End Sub
    'Open
    Private Sub เปดไฟลงานToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles เปดไฟลงานToolStripMenuItem.Click

        Dim lines() As String
        Dim data() As String

        lines = File.ReadAllLines("C:\Memoryคาร์แคร์\SAVE\MemorySave.Txt")

        For i As Integer = 0 To lines.Length - 1 Step +1

            data = lines(i).ToString().Split("l")
            Dim row(data.Length - 1) As String

            For j As Integer = 0 To data.Length - 1 Step +1

                row(j) = data(j).Trim

            Next j

            DataGridView1.Rows.Add(row)

        Next i

    End Sub
    'Save
    Private Sub บนทกงานToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles บนทกงานToolStripMenuItem.Click
        Dim writer As New StreamWriter("C:\Memoryคาร์แคร์\SAVE\MemorySave.Txt")

        For i As Integer = 0 To DataGridView1.Rows.Count - 2 Step +1

            For j As Integer = 0 To DataGridView1.Columns.Count - 1 Step +1

                If j = DataGridView1.Columns.Count - 1 Then
                    writer.Write(vbTab & DataGridView1.Rows(i).Cells(j).Value.ToString() & vbTab & "l")

                Else
                    writer.Write(vbTab & DataGridView1.Rows(i).Cells(j).Value.ToString() & vbTab & "l")

                End If

            Next j

            writer.WriteLine("")

        Next
        writer.Close()
        MessageBox.Show("บันทึกเรียบร้อย")
    End Sub
End Class