Visual Basic - Filtrar registros de un MSFlexGrid

Private Sub Buscar()

    If Len(Trim(txtBuscar)) < 3 Or txtBuscar = "<< Capture un proveedor o descripción >>" Then Exit Sub

    lstBuscar.Clear

    SqlCanQuery (SqlConn)

    strquery = "SELECT nompr, rfcpr, ciudd, a.idpro, isnull(b.correo, 'NO ESPECIFICADO'), isnull(claveweb, 'SIN CLAVE') FROM  proveedores a left join proveedoresdet b on a.idpro = b.idpro where nompr LIKE '%" & LTrim(RTrim(txtBuscar.Text)) & "%'"

    Result = SqlCmd(SqlConn, strquery)

    Result = SqlExec(SqlConn)

    Result = SqlResults(SqlConn)

On Error GoTo Salir

    If (Result = SUCCEED) Then

        Result = SqlNextRow(SqlConn)

        If (Result <> NOMOREROWS) Then

            Do

                lstBuscar.AddItem Trim(SqlData(SqlConn, 2)) + vbTab + Trim(SqlData(SqlConn, 1))

                Result = SqlNextRow(SqlConn)

            Loop Until (Result = NOMOREROWS)

        End If

        SqlCanQuery (SqlConn)

    End If

Salir:

    If lstBuscar.ListCount > 0 And Not lstBuscar.Visible Then lstBuscar.Visible = True

End Sub

With msfProvs

        For R = 0 To .Rows - 1  'Filas

            For C = 0 To .Cols - 1  'Columnas

                If InStr(1, .TextMatrix(R, C), txtBuscar.Text, vbTextCompare) > 0 Then

                    lstBuscar.AddItem .TextMatrix(R, 1) + vbTab + .TextMatrix(R, 0)

                End If

            Next C

        Next R

    End With

If lstBuscar.ListIndex > -1 Then

        fraBuscar.Visible = False

        msfProvs.Row = lstBuscar.ItemData(lstBuscar.ListIndex) + 1

        msfProvs.TopRow = msfProvs.Row

        msfProvs.SetFocus

End If

With msfProvs

        For R = 0 To .Rows - 1  'Filas

            For C = 0 To .Cols - 1  'Columnas

                If InStr(1, .TextMatrix(R, C), txtBuscar.Text, vbTextCompare) > 0 Then

                    lstBuscar.AddItem .TextMatrix(R, 1) + vbTab + .TextMatrix(R, 0)

                    lstBuscar.ItemData (lstBuscar.NewIndex) = R   '<--------- Aqui se le asigna el valor.

                End If

            Next C

        Next R

    End With

If lstBuscar.ListIndex > -1 Then

        fraBuscar.Visible = False

        msfProvs.Row = lstBuscar.ItemData(lstBuscar.ListIndex)

        msfProvs.TopRow = msfProvs.Row

        msfProvs.SetFocus

End If