Cara Membuat Fungsi Searcing

CARA MEMBUAT FUNGSI SEARCING PADA VB.NET

Imports System.Data
Imports System.Data.SqlClient

Public Class MasterObat
    Dim Cn As New SqlConnection("server=ONESIS-PC; User Id=ARIF; password=123456789; Database=Apotik")
    Dim Sql As String

    Sub Tampil()
        If Not Cn.State = ConnectionState.Open Then
            Cn.Open()
        End If
        Sql = " Select * from MasterObat "
        Dim da As New SqlDataAdapter(Sql, Cn)
        Dim dt As New DataTable
        da.Fill(dt)
        Me.DGV.DataSource = dt
        Cn.Close()
    End Sub

    Private Sub MasterObat_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Tampil()
    End Sub

    Private Sub Tcari_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Tcari.TextChanged
        If Tpilih.Text = "Kode_Obat" Then
            Sql = "Select * From MasterObat where Kode_Obat like '" & Tcari.Text & "%'"

        ElseIf Tpilih.Text = "Nama_Obat" Then
            Sql = "Select * from MasterObat where Nama_Obat like '" & Tcari.Text & "%'"

        ElseIf Tpilih.Text = "Satuan" Then
            Sql = "Select * from MasterObat where Satuan like '" & Tcari.Text & "%'"

        ElseIf Tpilih.Text = "Harga_Satuan" Then
            Sql = "Select * from MasterObat where Harga_Satuan =" & Val(Tcari.Text) & ""

        ElseIf Tpilih.Text = "Exspire" Then
            Sql = "Select * from MasterObat where Exspire like '%" & Val(Tcari.Text) & "%'"
        End If
        Dim da As New SqlDataAdapter(Sql, Cn)
        Dim dt As New DataTable
        da.Fill(dt)
        Me.DGV.DataSource = dt
        Cn.Close()
    End Sub
End Class